Diagnostics

Herbaceous Ornamentals

Alyssum (Lobularia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Aster (Aster)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Blister beetles (Meloidae family)
    Adults are about 1" long plus with soft, narrow, elongate bodies. Their wing-covers are rounded over the cylindrical body and their large heads are set off from the thorax. If handled, be warned that these beetles contain a defensive oil (cantharidin) which can cause skin to blister. There is one generation per year and adults are active from late May through September.
  • Chrysanthemum lacebug (Corythucha marmorata)
    Adult lacebugs are tiny, flat, creamy-white flying insects with lace-like wings held flat over the back. Look for groups of black eggs inserted on the undersides of leaves near veins, and brown, varnish-like frass, also on leaf undersides. Nymphs are covered in spines and have triangular shaped heads. Lacebugs overwinter as adults in protected areas near host plants. There may be up to 2 generations per year.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Common stalk borer (Papaipema nebris)
    Larvae are slender, striped caterpillars, 3/4" to 1-1/2" long. Young larvae have dark-brown or purple band around a cream-colored body and several brown or purple lengthwise stripes. Older larvae are grayish or light purple. Moths, which are grayish-brown with white spots on forewings, appear in August and September. Eggs overwinter on grasses and weeds. There is only 1 generation per year.
  • Cucumber beetle (Spotted/Striped) (Chrysomelidae family (CB))
    Larvae are pale-colored and wormlike with brown heads. Adult spotted cucumber beetles are about 1/4" long, with shiny black heads and greenish-yellow with 12 black spots on their backs. Adult striped cucumber beetles are about 1/4" long, with shiny black heads and are yellowish-orange with 3 black stripes. There may be 1-2 generations of each type of cucumber beetle per year.
  • Cucumber mosaic (Cucumber mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Viruses can retard plant growth and change the appearance of foliage, flowers and fruits. Virus-infected leaves can become spotted, streaked or mottled; they may be distorted or stunted. Veins may lose their color or develop outgrowths. Flowers can be dwarfed, deformed, streaked, faded, or they can remain green and develop into leaf-like structures.
  • Cyclamen and Broad mites (Tarsonemidae family)
    Miniscule mites, often less than 1/80", are colorless or may have a pale brown tint. Can develop rapidly, with generation times completed in about 1 week. If temperature conditions are favorable, cyclamen mites can reproduce continually. Goes dormant in winter and reactivates in spring. Cyclamen and broad mites have different genera, but cause similar damage and are impossible to ID without high magnification. Broad mites are restricted to greenhouses in our area.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Downy mildew (herbaceous) (Several)
    Early symptoms appear as irregular, light green or yellow angular patches on upper leaf surfaces. Lesions may also be purplish red to dark brown. Under high humidity, downy mildews form fluffy or fuzzy (downy) areas of spores on the undersides of leaves. Under magnification, the downy areas look like very small bunches of branched hairs. Older leaves toward the bottom of plants are usually infected first and wither and brown as the disease proceeds up the stem.
  • Earwig (Forficula auricularia)
    Adults are about 1/2" long with prominent pincers on their hind ends, and reddish brown with lighter-colored, short wing covers on the thorax. Earwigs overwinter in the adult stage. Females lay eggs twice in a season, but there is only 1 generation per year. Foraging occurs at night, with movement to dark, sheltered areas during the day.
  • Flea beetle (Chrysomelidae family)
    Flea beetles are among the smallest of the leaf beetles, typically smaller than 1/6" long. They usually possess large rear legs used for jumping. Several species are found in Wisconsin.
  • Four-lined plant bug (Poecilocapsus lineatus)
    Adults are 1/4-1/3" long, and yellow to yellow-green with four longitudinal black lines down the wing covers, and black antennae. Nymphs are bright red-orange with black dots on the abdomen. Insect has a short lifecyle beginning in late April/early May. Adult activity outdoors is over by the end of spring. One generation produced annually.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Rusts (herbaceous) (Several)
    Symptoms of infection usually first appear as light-colored spots on upper leaf surfaces followed by dry, brown, orange, purple, reddish or yellowish spore masses or pustules commonly on the lower leaf surfaces. Each rust species is specific to a certain host genus or species and cannot spread to unrelated plants. Moderate infections will not harm plants, but can make plants unattractive. Heavily infected leaves may curl, wither and drop prematurely. Severely infected plants may be stunted. Rusts spread primarily via windblown spores.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Southern blight (Sclerotium rolfsii)
    This disease is only active during hot weather. Plants may grow well in infested soil during most of the growing season and only be damaged during the hottest part of summer. Initial symptoms are yellowing or wilting of lower leaves, then basal stems decay, followed by the collapse of individual stems or entire plants. Inspection of the stem at the soil line reveals white mycelium (fungal strands) and small, tan spherical sclerotia (fungal survival structures) that resemble mustard seeds. Roots are unaffected. Decay of the stem at the soil line is common during hot, humid weather.
  • Tarnished plant bug (Lygus lineolaris)
    Adults are 1/4" long, generally oval and about twice as long as wide. They are usually brownish with some yellow and reddish markings. Insect color tends to darken with age. Nymphs are more rounded, yellowish green to dark green, and often have dark spots. Adults overwinter in sheltered sites and become active in early spring. Several generations are produced annually.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.
  • Wireworm (Elateridae family)
    Wireworms are soil-dwelling larvae of click beetles, 1/4 -1/2" long. They are yellow-brown with dark heads, long, thin and cylindrical with tough skins. The larvae have small thoracic legs and powerful mandibles for chewing. Wireworms have an extended life cycle, taking from 1-6 years to complete one generation. They overwinter as either adults or larvae.

Beard tongue (Penstemon)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Black-eyed Susan (Rudbeckia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Buttercup (Ranunculus)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Butterfly weed (Asclepias)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.

Canna lily (Canna)

  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cucumber beetle (Spotted/Striped) (Chrysomelidae family (CB))
    Larvae are pale-colored and wormlike with brown heads. Adult spotted cucumber beetles are about 1/4" long, with shiny black heads and greenish-yellow with 12 black spots on their backs. Adult striped cucumber beetles are about 1/4" long, with shiny black heads and are yellowish-orange with 3 black stripes. There may be 1-2 generations of each type of cucumber beetle per year.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.

Chrysanthemum (Dendranthema)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Common periwinkle (Vinca)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Cornflower, Knapweed (Centaurea)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Common stalk borer (Papaipema nebris)
    Larvae are slender, striped caterpillars, 3/4" to 1-1/2" long. Young larvae have dark-brown or purple band around a cream-colored body and several brown or purple lengthwise stripes. Older larvae are grayish or light purple. Moths, which are grayish-brown with white spots on forewings, appear in August and September. Eggs overwinter on grasses and weeds. There is only 1 generation per year.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Downy mildew (herbaceous) (Several)
    Early symptoms appear as irregular, light green or yellow angular patches on upper leaf surfaces. Lesions may also be purplish red to dark brown. Under high humidity, downy mildews form fluffy or fuzzy (downy) areas of spores on the undersides of leaves. Under magnification, the downy areas look like very small bunches of branched hairs. Older leaves toward the bottom of plants are usually infected first and wither and brown as the disease proceeds up the stem.
  • Fusarium wilt (Fusarium species (H))
    Infected plants wilt and die. Foliage yellows, curls, wilts, then browns and dies. Lower foliage is usually affected first. In many hosts, symptoms may appear only on one side of the plant. If you take a cross-section of the basal stem, vascular tissues may be discolored and you may see brown rings or solid brown coloration, often from the soil line to shoots.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Rusts (herbaceous) (Several)
    Symptoms of infection usually first appear as light-colored spots on upper leaf surfaces followed by dry, brown, orange, purple, reddish or yellowish spore masses or pustules commonly on the lower leaf surfaces. Each rust species is specific to a certain host genus or species and cannot spread to unrelated plants. Moderate infections will not harm plants, but can make plants unattractive. Heavily infected leaves may curl, wither and drop prematurely. Severely infected plants may be stunted. Rusts spread primarily via windblown spores.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Cyclamen (Cyclamen)

  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cyclamen and Broad mites (Tarsonemidae family)
    Miniscule mites, often less than 1/80", are colorless or may have a pale brown tint. Can develop rapidly, with generation times completed in about 1 week. If temperature conditions are favorable, cyclamen mites can reproduce continually. Goes dormant in winter and reactivates in spring. Cyclamen and broad mites have different genera, but cause similar damage and are impossible to ID without high magnification. Broad mites are restricted to greenhouses in our area.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Ralstonia wilt (Ralstonia solanacearum)
    Initially, lower leaves of infected plants yellow and wilt, then die. Yellowing and death of upper leaves follow. Symptoms may initially occur on only one side of the plant. Internally, the water-conducting tissue of the plant browns, and then the entire stem rots from the inside out. Finally, infected plants die. One race of this bacteria can cause a serious disease of potatoes, thus it is closely monitored by various government agencies.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Dahlia (Dahlia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Daisy (Argyranthemum)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Bacterial soft rot (Erwinia species)
    Causes infected tissue to turn brown and mushy with a disagreeable odor. Stem tissue can brown and deteriorate at or near the soil line. Other symptoms may include slow overall plant growth and seedling collapse. In bearded iris, this disease often infects at the feeding sites of iris borers, which hatch on leaves, burrowing into them (often leaving a water-soaked spot) and tunneling down into the rhizome.
  • Blister beetles (Meloidae family)
    Adults are about 1" long plus with soft, narrow, elongate bodies. Their wing-covers are rounded over the cylindrical body and their large heads are set off from the thorax. If handled, be warned that these beetles contain a defensive oil (cantharidin) which can cause skin to blister. There is one generation per year and adults are active from late May through September.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Common stalk borer (Papaipema nebris)
    Larvae are slender, striped caterpillars, 3/4" to 1-1/2" long. Young larvae have dark-brown or purple band around a cream-colored body and several brown or purple lengthwise stripes. Older larvae are grayish or light purple. Moths, which are grayish-brown with white spots on forewings, appear in August and September. Eggs overwinter on grasses and weeds. There is only 1 generation per year.
  • Cucumber beetle (Spotted/Striped) (Chrysomelidae family (CB))
    Larvae are pale-colored and wormlike with brown heads. Adult spotted cucumber beetles are about 1/4" long, with shiny black heads and greenish-yellow with 12 black spots on their backs. Adult striped cucumber beetles are about 1/4" long, with shiny black heads and are yellowish-orange with 3 black stripes. There may be 1-2 generations of each type of cucumber beetle per year.
  • Cyclamen and Broad mites (Tarsonemidae family)
    Miniscule mites, often less than 1/80", are colorless or may have a pale brown tint. Can develop rapidly, with generation times completed in about 1 week. If temperature conditions are favorable, cyclamen mites can reproduce continually. Goes dormant in winter and reactivates in spring. Cyclamen and broad mites have different genera, but cause similar damage and are impossible to ID without high magnification. Broad mites are restricted to greenhouses in our area.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Four-lined plant bug (Poecilocapsus lineatus)
    Adults are 1/4-1/3" long, and yellow to yellow-green with four longitudinal black lines down the wing covers, and black antennae. Nymphs are bright red-orange with black dots on the abdomen. Insect has a short lifecyle beginning in late April/early May. Adult activity outdoors is over by the end of spring. One generation produced annually.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Rose chafer (Macrodactylus subspinosus)
    Adults are about 1/2" long, elongate, with gray or tan bodies and long, spiny orange or dark-brown legs. Their distinctive antennae have fringes at the tips. Larvae feed on roots of grasses and some weeds, apparently causing little injury. Adult damage occurs in June, and can be most severe in areas with light, sandy soil. Heavy or clay soils can hamper growth and development. Larvae overwinter in soil just below the frostline.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Slug (Order Sytlomatophora)
    Garden slugs are terrestrial mollusks, essentially snails without shells. As they move, they coat surfaces with a silvery, slimy substance. Most feed at night or during dark, cloudy days. Trails and feeding injuries are usually noticed before the slug itself. Slugs overwinter either as adults or as eggs. They become active during the first warm days of spring, and thrive under cool, damp conditions. Populations will be high during/following damp, rainy weather, and will almost disappear during dry periods. Slugs cannot survive direct sunlight. Rock walls, boards, pots and plant debris, as well as shaded flower beds and heavily mulched gardens, serve as ideal daytime resting sites.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Tarnished plant bug (Lygus lineolaris)
    Adults are 1/4" long, generally oval and about twice as long as wide. They are usually brownish with some yellow and reddish markings. Insect color tends to darken with age. Nymphs are more rounded, yellowish green to dark green, and often have dark spots. Adults overwinter in sheltered sites and become active in early spring. Several generations are produced annually.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.
  • Wireworm (Elateridae family)
    Wireworms are soil-dwelling larvae of click beetles, 1/4 -1/2" long. They are yellow-brown with dark heads, long, thin and cylindrical with tough skins. The larvae have small thoracic legs and powerful mandibles for chewing. Wireworms have an extended life cycle, taking from 1-6 years to complete one generation. They overwinter as either adults or larvae.

Fuchsia (Fuchsia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Geranium (Pelargonium)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Gerber daisy (Gerbera)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Gloxinia (Gloxinia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Groundsel, Cineraria (Senecio)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Hollyhock (Alcea)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Common stalk borer (Papaipema nebris)
    Larvae are slender, striped caterpillars, 3/4" to 1-1/2" long. Young larvae have dark-brown or purple band around a cream-colored body and several brown or purple lengthwise stripes. Older larvae are grayish or light purple. Moths, which are grayish-brown with white spots on forewings, appear in August and September. Eggs overwinter on grasses and weeds. There is only 1 generation per year.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Earwig (Forficula auricularia)
    Adults are about 1/2" long with prominent pincers on their hind ends, and reddish brown with lighter-colored, short wing covers on the thorax. Earwigs overwinter in the adult stage. Females lay eggs twice in a season, but there is only 1 generation per year. Foraging occurs at night, with movement to dark, sheltered areas during the day.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Rusts (herbaceous) (Several)
    Symptoms of infection usually first appear as light-colored spots on upper leaf surfaces followed by dry, brown, orange, purple, reddish or yellowish spore masses or pustules commonly on the lower leaf surfaces. Each rust species is specific to a certain host genus or species and cannot spread to unrelated plants. Moderate infections will not harm plants, but can make plants unattractive. Heavily infected leaves may curl, wither and drop prematurely. Severely infected plants may be stunted. Rusts spread primarily via windblown spores.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Slug (Order Sytlomatophora)
    Garden slugs are terrestrial mollusks, essentially snails without shells. As they move, they coat surfaces with a silvery, slimy substance. Most feed at night or during dark, cloudy days. Trails and feeding injuries are usually noticed before the slug itself. Slugs overwinter either as adults or as eggs. They become active during the first warm days of spring, and thrive under cool, damp conditions. Populations will be high during/following damp, rainy weather, and will almost disappear during dry periods. Slugs cannot survive direct sunlight. Rock walls, boards, pots and plant debris, as well as shaded flower beds and heavily mulched gardens, serve as ideal daytime resting sites.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Tarnished plant bug (Lygus lineolaris)
    Adults are 1/4" long, generally oval and about twice as long as wide. They are usually brownish with some yellow and reddish markings. Insect color tends to darken with age. Nymphs are more rounded, yellowish green to dark green, and often have dark spots. Adults overwinter in sheltered sites and become active in early spring. Several generations are produced annually.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Hyacinth (Hyacinth)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Lantana (Lantana)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Larkspur (Delphinium)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Lobelia (Lobelia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Madagascar periwinkle (Catharanthus)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Mallow (Malva)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Mint (Mentha)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Oregano (Origanum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Pansy (Viola)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Peony (Paeonia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Persian violet (Exacum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Pinks (Dianthus)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Primrose (Primula (sometimes Polyanthus))

  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Salvia, sage (Salvia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Spike (Dracaena)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Statice (Limonium)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Stock (Matthiola)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Sunflower (Helianthus)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Tulip (Tulipa)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Verbena (Verbena)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Woodrush (Luzula)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Herbaceous Ornamentals-Annuals

Basil (Ocimum)

  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.

Begonia (Begonia)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cucumber mosaic (Cucumber mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Viruses can retard plant growth and change the appearance of foliage, flowers and fruits. Virus-infected leaves can become spotted, streaked or mottled; they may be distorted or stunted. Veins may lose their color or develop outgrowths. Flowers can be dwarfed, deformed, streaked, faded, or they can remain green and develop into leaf-like structures.
  • Cyclamen and Broad mites (Tarsonemidae family)
    Miniscule mites, often less than 1/80", are colorless or may have a pale brown tint. Can develop rapidly, with generation times completed in about 1 week. If temperature conditions are favorable, cyclamen mites can reproduce continually. Goes dormant in winter and reactivates in spring. Cyclamen and broad mites have different genera, but cause similar damage and are impossible to ID without high magnification. Broad mites are restricted to greenhouses in our area.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Rhizoctonia web blight (Rhizoctonia species (H))
    This disease is favored by high temperatures and high humidity, especially in the greenhouse setting. Symptoms appear as irregular, brown spots which can form anywhere on foliage or stems. In high humidity, web-like brown mycelium can cover infected portions of the plant host. Rhizoctonia is a soil-borne pathogen.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.

Cockscomb (Celosia)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Tobacco mosaic (Tobacco mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Mosaic symptoms are characterized by intermingled patches of normal and light green or yellowish colors on the leaves of infected plants. TMV damages the leaves, flowers and fruit, and causes stunting of the plant. It almost never kills the plants, but lowers the quality and quantity of the crop, particularly when plants are infected while young.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Coleus (Coleus)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Downy mildew (herbaceous) (Several)
    Early symptoms appear as irregular, light green or yellow angular patches on upper leaf surfaces. Lesions may also be purplish red to dark brown. Under high humidity, downy mildews form fluffy or fuzzy (downy) areas of spores on the undersides of leaves. Under magnification, the downy areas look like very small bunches of branched hairs. Older leaves toward the bottom of plants are usually infected first and wither and brown as the disease proceeds up the stem.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.

Cosmos (Cosmos)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Common stalk borer (Papaipema nebris)
    Larvae are slender, striped caterpillars, 3/4" to 1-1/2" long. Young larvae have dark-brown or purple band around a cream-colored body and several brown or purple lengthwise stripes. Older larvae are grayish or light purple. Moths, which are grayish-brown with white spots on forewings, appear in August and September. Eggs overwinter on grasses and weeds. There is only 1 generation per year.
  • Cucumber beetle (Spotted/Striped) (Chrysomelidae family (CB))
    Larvae are pale-colored and wormlike with brown heads. Adult spotted cucumber beetles are about 1/4" long, with shiny black heads and greenish-yellow with 12 black spots on their backs. Adult striped cucumber beetles are about 1/4" long, with shiny black heads and are yellowish-orange with 3 black stripes. There may be 1-2 generations of each type of cucumber beetle per year.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Four-lined plant bug (Poecilocapsus lineatus)
    Adults are 1/4-1/3" long, and yellow to yellow-green with four longitudinal black lines down the wing covers, and black antennae. Nymphs are bright red-orange with black dots on the abdomen. Insect has a short lifecyle beginning in late April/early May. Adult activity outdoors is over by the end of spring. One generation produced annually.
  • Fusarium wilt (Fusarium species (H))
    Infected plants wilt and die. Foliage yellows, curls, wilts, then browns and dies. Lower foliage is usually affected first. In many hosts, symptoms may appear only on one side of the plant. If you take a cross-section of the basal stem, vascular tissues may be discolored and you may see brown rings or solid brown coloration, often from the soil line to shoots.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Ralstonia wilt (Ralstonia solanacearum)
    Initially, lower leaves of infected plants yellow and wilt, then die. Yellowing and death of upper leaves follow. Symptoms may initially occur on only one side of the plant. Internally, the water-conducting tissue of the plant browns, and then the entire stem rots from the inside out. Finally, infected plants die. One race of this bacteria can cause a serious disease of potatoes, thus it is closely monitored by various government agencies.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Tarnished plant bug (Lygus lineolaris)
    Adults are 1/4" long, generally oval and about twice as long as wide. They are usually brownish with some yellow and reddish markings. Insect color tends to darken with age. Nymphs are more rounded, yellowish green to dark green, and often have dark spots. Adults overwinter in sheltered sites and become active in early spring. Several generations are produced annually.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Flossflower (Ageratum)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cyclamen and Broad mites (Tarsonemidae family)
    Miniscule mites, often less than 1/80", are colorless or may have a pale brown tint. Can develop rapidly, with generation times completed in about 1 week. If temperature conditions are favorable, cyclamen mites can reproduce continually. Goes dormant in winter and reactivates in spring. Cyclamen and broad mites have different genera, but cause similar damage and are impossible to ID without high magnification. Broad mites are restricted to greenhouses in our area.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Root rot (Fusarium species (W))
    Symptoms include stunting, chlorosis, root necrosis and death of woody plants. Symptoms are dependent on cultural practices and the local environment.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.

Flowering tobacco (Nicotiana)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Fountain plant, Love-lies-bleeding (Amaranth)

  • Blister beetles (Meloidae family)
    Adults are about 1" long plus with soft, narrow, elongate bodies. Their wing-covers are rounded over the cylindrical body and their large heads are set off from the thorax. If handled, be warned that these beetles contain a defensive oil (cantharidin) which can cause skin to blister. There is one generation per year and adults are active from late May through September.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Leafhoppers (Several)
    3-15 mm in length, wedge shaped with wings that peak over their backs. Nymphs are wingless but active and move readily when disturbed. Adults are winged and fly readily when disturbed.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.

Globe amaranth (Gomphrena)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Impatiens (Impatiens)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Marigold (Tagetes)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Morning glory (Ipomea)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Nasturtium (Tropaeolum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Ornamental pepper (Capsicum)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Anthracnose (herbaceous) (Several)
    Symptoms typically appear as tan to brown spots or sunken lesions that may combine to form irregular, dark lesions that cause rapid blighting of leaves or stems. Depending on the fungus species and host plant species, foliage may also distort, turn yellow, wilt, drop prematurely or die. This may cause signficant plant losses if not diagnosed in the early stages of infection. Under wet conditions, these diseases can have multiple infection cycles during the growing season. Anthracnose fungi persist primarily in infected plant parts and crop debris.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cucumber mosaic (Cucumber mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Viruses can retard plant growth and change the appearance of foliage, flowers and fruits. Virus-infected leaves can become spotted, streaked or mottled; they may be distorted or stunted. Veins may lose their color or develop outgrowths. Flowers can be dwarfed, deformed, streaked, faded, or they can remain green and develop into leaf-like structures.
  • Cutworms (Black/Variegated) (Noctuidae family)
    Variegated cutworm larvae have pale-yellow spots on the back of most body segments with a dark W-mark usually present on the 8th abdominal segment. They are usually active at night. Adult moths are ashy, or light dirty brown with dark brown mottling. Pupae overwinter in soil. Moths lay eggs on leaves, stems of plants and possibly on inanimate objects such as fences and buildings. There are usually 2 generations a year. Black cutworm larvae are gray brown to black with a somewhat greasy sheen. They are also nocturnal feeders. 3 generations are common in WI. Adults don't survive Northern winters, but are strongly migratory. Adult moths have a 2" wingspan and are uniformly dark brown with a black daggerlike marking on the forewing. All species of cutworms curl up into a tight "C" when disturbed.
  • Cyclamen and Broad mites (Tarsonemidae family)
    Miniscule mites, often less than 1/80", are colorless or may have a pale brown tint. Can develop rapidly, with generation times completed in about 1 week. If temperature conditions are favorable, cyclamen mites can reproduce continually. Goes dormant in winter and reactivates in spring. Cyclamen and broad mites have different genera, but cause similar damage and are impossible to ID without high magnification. Broad mites are restricted to greenhouses in our area.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Flea beetle (Chrysomelidae family)
    Flea beetles are among the smallest of the leaf beetles, typically smaller than 1/6" long. They usually possess large rear legs used for jumping. Several species are found in Wisconsin.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora blight (herbaceous) (Phytophthora species (H))
    Symptoms appear as dark brown to black leathery tissue on plant parts, but commonly the lower halves of young shoots, stems or the bases of blighted leaves. Shoots may wilt and collapse. Severe infection may affect the entire crown. If you cut into the stem, vascular tissues show brown, olive green, reddish or dark streaking. Phytophthora is a 'water mold' and it is favored by frequent irrigation and wet, slow draining soils. Saturated soils encourage spore production, causing more severe disease.
  • Ralstonia wilt (Ralstonia solanacearum)
    Initially, lower leaves of infected plants yellow and wilt, then die. Yellowing and death of upper leaves follow. Symptoms may initially occur on only one side of the plant. Internally, the water-conducting tissue of the plant browns, and then the entire stem rots from the inside out. Finally, infected plants die. One race of this bacteria can cause a serious disease of potatoes, thus it is closely monitored by various government agencies.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Southern blight (Sclerotium rolfsii)
    This disease is only active during hot weather. Plants may grow well in infested soil during most of the growing season and only be damaged during the hottest part of summer. Initial symptoms are yellowing or wilting of lower leaves, then basal stems decay, followed by the collapse of individual stems or entire plants. Inspection of the stem at the soil line reveals white mycelium (fungal strands) and small, tan spherical sclerotia (fungal survival structures) that resemble mustard seeds. Roots are unaffected. Decay of the stem at the soil line is common during hot, humid weather.
  • Tarnished plant bug (Lygus lineolaris)
    Adults are 1/4" long, generally oval and about twice as long as wide. They are usually brownish with some yellow and reddish markings. Insect color tends to darken with age. Nymphs are more rounded, yellowish green to dark green, and often have dark spots. Adults overwinter in sheltered sites and become active in early spring. Several generations are produced annually.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Tobacco mosaic (Tobacco mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Mosaic symptoms are characterized by intermingled patches of normal and light green or yellowish colors on the leaves of infected plants. TMV damages the leaves, flowers and fruit, and causes stunting of the plant. It almost never kills the plants, but lowers the quality and quantity of the crop, particularly when plants are infected while young.
  • Verticillium wilt (herbaceous) (Verticillium species (H))
    Infected plants wilt, turn yellow, then brown-progressing upwards from the base to the tip of the plant or branch, and then they die. Browning of older leaves while younger leaves remain green is also characteristic. If you cut into the stem, vascular tissues show discoloration as brown, olive green, reddish or dark streaking. Verticillium usually infects during cool conditions, but damage may not become apparent until warm weather and the plant is stressed. It is favored by droughty conditions.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Wireworm (Elateridae family)
    Wireworms are soil-dwelling larvae of click beetles, 1/4 -1/2" long. They are yellow-brown with dark heads, long, thin and cylindrical with tough skins. The larvae have small thoracic legs and powerful mandibles for chewing. Wireworms have an extended life cycle, taking from 1-6 years to complete one generation. They overwinter as either adults or larvae.

Petunia (Petunia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Pot marigold (Calendula)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Blister beetles (Meloidae family)
    Adults are about 1" long plus with soft, narrow, elongate bodies. Their wing-covers are rounded over the cylindrical body and their large heads are set off from the thorax. If handled, be warned that these beetles contain a defensive oil (cantharidin) which can cause skin to blister. There is one generation per year and adults are active from late May through September.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Common stalk borer (Papaipema nebris)
    Larvae are slender, striped caterpillars, 3/4" to 1-1/2" long. Young larvae have dark-brown or purple band around a cream-colored body and several brown or purple lengthwise stripes. Older larvae are grayish or light purple. Moths, which are grayish-brown with white spots on forewings, appear in August and September. Eggs overwinter on grasses and weeds. There is only 1 generation per year.
  • Cucumber beetle (Spotted/Striped) (Chrysomelidae family (CB))
    Larvae are pale-colored and wormlike with brown heads. Adult spotted cucumber beetles are about 1/4" long, with shiny black heads and greenish-yellow with 12 black spots on their backs. Adult striped cucumber beetles are about 1/4" long, with shiny black heads and are yellowish-orange with 3 black stripes. There may be 1-2 generations of each type of cucumber beetle per year.
  • Cucumber mosaic (Cucumber mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Viruses can retard plant growth and change the appearance of foliage, flowers and fruits. Virus-infected leaves can become spotted, streaked or mottled; they may be distorted or stunted. Veins may lose their color or develop outgrowths. Flowers can be dwarfed, deformed, streaked, faded, or they can remain green and develop into leaf-like structures.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Tarnished plant bug (Lygus lineolaris)
    Adults are 1/4" long, generally oval and about twice as long as wide. They are usually brownish with some yellow and reddish markings. Insect color tends to darken with age. Nymphs are more rounded, yellowish green to dark green, and often have dark spots. Adults overwinter in sheltered sites and become active in early spring. Several generations are produced annually.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.

Slipper flower (Calceolaria)

  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.

Snapdragon (Antirrhinum)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Common stalk borer (Papaipema nebris)
    Larvae are slender, striped caterpillars, 3/4" to 1-1/2" long. Young larvae have dark-brown or purple band around a cream-colored body and several brown or purple lengthwise stripes. Older larvae are grayish or light purple. Moths, which are grayish-brown with white spots on forewings, appear in August and September. Eggs overwinter on grasses and weeds. There is only 1 generation per year.
  • Cucumber mosaic (Cucumber mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Viruses can retard plant growth and change the appearance of foliage, flowers and fruits. Virus-infected leaves can become spotted, streaked or mottled; they may be distorted or stunted. Veins may lose their color or develop outgrowths. Flowers can be dwarfed, deformed, streaked, faded, or they can remain green and develop into leaf-like structures.
  • Cyclamen and Broad mites (Tarsonemidae family)
    Miniscule mites, often less than 1/80", are colorless or may have a pale brown tint. Can develop rapidly, with generation times completed in about 1 week. If temperature conditions are favorable, cyclamen mites can reproduce continually. Goes dormant in winter and reactivates in spring. Cyclamen and broad mites have different genera, but cause similar damage and are impossible to ID without high magnification. Broad mites are restricted to greenhouses in our area.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Downy mildew (herbaceous) (Several)
    Early symptoms appear as irregular, light green or yellow angular patches on upper leaf surfaces. Lesions may also be purplish red to dark brown. Under high humidity, downy mildews form fluffy or fuzzy (downy) areas of spores on the undersides of leaves. Under magnification, the downy areas look like very small bunches of branched hairs. Older leaves toward the bottom of plants are usually infected first and wither and brown as the disease proceeds up the stem.
  • Four-lined plant bug (Poecilocapsus lineatus)
    Adults are 1/4-1/3" long, and yellow to yellow-green with four longitudinal black lines down the wing covers, and black antennae. Nymphs are bright red-orange with black dots on the abdomen. Insect has a short lifecyle beginning in late April/early May. Adult activity outdoors is over by the end of spring. One generation produced annually.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Rusts (herbaceous) (Several)
    Symptoms of infection usually first appear as light-colored spots on upper leaf surfaces followed by dry, brown, orange, purple, reddish or yellowish spore masses or pustules commonly on the lower leaf surfaces. Each rust species is specific to a certain host genus or species and cannot spread to unrelated plants. Moderate infections will not harm plants, but can make plants unattractive. Heavily infected leaves may curl, wither and drop prematurely. Severely infected plants may be stunted. Rusts spread primarily via windblown spores.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Tarnished plant bug (Lygus lineolaris)
    Adults are 1/4" long, generally oval and about twice as long as wide. They are usually brownish with some yellow and reddish markings. Insect color tends to darken with age. Nymphs are more rounded, yellowish green to dark green, and often have dark spots. Adults overwinter in sheltered sites and become active in early spring. Several generations are produced annually.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Tobacco mosaic (Tobacco mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Mosaic symptoms are characterized by intermingled patches of normal and light green or yellowish colors on the leaves of infected plants. TMV damages the leaves, flowers and fruit, and causes stunting of the plant. It almost never kills the plants, but lowers the quality and quantity of the crop, particularly when plants are infected while young.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • Verticillium wilt (herbaceous) (Verticillium species (H))
    Infected plants wilt, turn yellow, then brown-progressing upwards from the base to the tip of the plant or branch, and then they die. Browning of older leaves while younger leaves remain green is also characteristic. If you cut into the stem, vascular tissues show discoloration as brown, olive green, reddish or dark streaking. Verticillium usually infects during cool conditions, but damage may not become apparent until warm weather and the plant is stressed. It is favored by droughty conditions.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Strawflower (Helichrysum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Sweet pea (Lathyrus)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Zinnia (Zinnia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Herbaceous Ornamentals-Perennials

Anemone (Anemone)

  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Blister beetles (Meloidae family)
    Adults are about 1" long plus with soft, narrow, elongate bodies. Their wing-covers are rounded over the cylindrical body and their large heads are set off from the thorax. If handled, be warned that these beetles contain a defensive oil (cantharidin) which can cause skin to blister. There is one generation per year and adults are active from late May through September.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cutworms (Black/Variegated) (Noctuidae family)
    Variegated cutworm larvae have pale-yellow spots on the back of most body segments with a dark W-mark usually present on the 8th abdominal segment. They are usually active at night. Adult moths are ashy, or light dirty brown with dark brown mottling. Pupae overwinter in soil. Moths lay eggs on leaves, stems of plants and possibly on inanimate objects such as fences and buildings. There are usually 2 generations a year. Black cutworm larvae are gray brown to black with a somewhat greasy sheen. They are also nocturnal feeders. 3 generations are common in WI. Adults don't survive Northern winters, but are strongly migratory. Adult moths have a 2" wingspan and are uniformly dark brown with a black daggerlike marking on the forewing. All species of cutworms curl up into a tight "C" when disturbed.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Downy mildew (herbaceous) (Several)
    Early symptoms appear as irregular, light green or yellow angular patches on upper leaf surfaces. Lesions may also be purplish red to dark brown. Under high humidity, downy mildews form fluffy or fuzzy (downy) areas of spores on the undersides of leaves. Under magnification, the downy areas look like very small bunches of branched hairs. Older leaves toward the bottom of plants are usually infected first and wither and brown as the disease proceeds up the stem.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Rusts (herbaceous) (Several)
    Symptoms of infection usually first appear as light-colored spots on upper leaf surfaces followed by dry, brown, orange, purple, reddish or yellowish spore masses or pustules commonly on the lower leaf surfaces. Each rust species is specific to a certain host genus or species and cannot spread to unrelated plants. Moderate infections will not harm plants, but can make plants unattractive. Heavily infected leaves may curl, wither and drop prematurely. Severely infected plants may be stunted. Rusts spread primarily via windblown spores.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Wireworm (Elateridae family)
    Wireworms are soil-dwelling larvae of click beetles, 1/4 -1/2" long. They are yellow-brown with dark heads, long, thin and cylindrical with tough skins. The larvae have small thoracic legs and powerful mandibles for chewing. Wireworms have an extended life cycle, taking from 1-6 years to complete one generation. They overwinter as either adults or larvae.

Avens (Geum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Balloon flower (Platycodon)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Barrenwort (Epimedium)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Bee balm, Bergamot (Monarda)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Bellflower (Campanula)

  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Rusts (herbaceous) (Several)
    Symptoms of infection usually first appear as light-colored spots on upper leaf surfaces followed by dry, brown, orange, purple, reddish or yellowish spore masses or pustules commonly on the lower leaf surfaces. Each rust species is specific to a certain host genus or species and cannot spread to unrelated plants. Moderate infections will not harm plants, but can make plants unattractive. Heavily infected leaves may curl, wither and drop prematurely. Severely infected plants may be stunted. Rusts spread primarily via windblown spores.
  • Slug (Order Sytlomatophora)
    Garden slugs are terrestrial mollusks, essentially snails without shells. As they move, they coat surfaces with a silvery, slimy substance. Most feed at night or during dark, cloudy days. Trails and feeding injuries are usually noticed before the slug itself. Slugs overwinter either as adults or as eggs. They become active during the first warm days of spring, and thrive under cool, damp conditions. Populations will be high during/following damp, rainy weather, and will almost disappear during dry periods. Slugs cannot survive direct sunlight. Rock walls, boards, pots and plant debris, as well as shaded flower beds and heavily mulched gardens, serve as ideal daytime resting sites.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.

Blackberry lily (Belamcanda)

  • Anthracnose (herbaceous) (Several)
    Symptoms typically appear as tan to brown spots or sunken lesions that may combine to form irregular, dark lesions that cause rapid blighting of leaves or stems. Depending on the fungus species and host plant species, foliage may also distort, turn yellow, wilt, drop prematurely or die. This may cause signficant plant losses if not diagnosed in the early stages of infection. Under wet conditions, these diseases can have multiple infection cycles during the growing season. Anthracnose fungi persist primarily in infected plant parts and crop debris.
  • Bacterial soft rot (Erwinia species)
    Causes infected tissue to turn brown and mushy with a disagreeable odor. Stem tissue can brown and deteriorate at or near the soil line. Other symptoms may include slow overall plant growth and seedling collapse. In bearded iris, this disease often infects at the feeding sites of iris borers, which hatch on leaves, burrowing into them (often leaving a water-soaked spot) and tunneling down into the rhizome.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Iris borer (Macronoctua onusta)
    Iris borer larvae range in color depending on the instar cycle. They start out translucent yellow (first instar) and end up pink to orange (last instar). Pupal cases are shiny and brown and larvae pupate in rhizomes. Adult moths are mottled brown with yellow-brown hind wings. Eggs are almost spherical and whitish-green. They are laid on leaves before foliage yellows and dies back in the fall. Eggs overwinter on old foliage and other plant debris.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Bleeding heart (Dicentra)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Bugleweed (Ajuga)

  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Candy tuft (Iberis)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Cat mint (Nepeta)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Catchfly, Maltese cross, Rose campion (Lychnis)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Columbine (Aquilegia)

  • Columbine leafminer (Phytomyza aquilegivora)
    Adults are miniscule (1-2mm, including wings), and are mostly black. Pupation occurs in an orange puparium frequently attached to the lower leaf surface close to the end of a mine. Two generations are produced annually.
  • Columbine splotch leafminer (Phytomyza aquilegiana)
    Adults are 2-2.5mm long and black. Pupae are reddish-brown and pupation occurs in the ground. Two generations are produced annually.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cucumber mosaic (Cucumber mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Viruses can retard plant growth and change the appearance of foliage, flowers and fruits. Virus-infected leaves can become spotted, streaked or mottled; they may be distorted or stunted. Veins may lose their color or develop outgrowths. Flowers can be dwarfed, deformed, streaked, faded, or they can remain green and develop into leaf-like structures.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.

Common or Rose Mallow (Althaea)

  • Bacterial leaf spot & twig blight (Pseudomonas syringae pv. Syringae)
    Initial symptoms of bacterial blight may include dark brown necrotic (dead) leaf spots with yellow margins. If leaf spots develop before leaves are fully expanded, leaf curling and twisting may result. More advanced symptoms include necrotic blotches starting at the leaf margins and advancing inward, as well as black streaking on twigs. In its' most severe form, bacterial blight can result in the death of branch tips, leaves and blossoms.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Root rot (woody plants) (Pythium species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Rusts (herbaceous) (Several)
    Symptoms of infection usually first appear as light-colored spots on upper leaf surfaces followed by dry, brown, orange, purple, reddish or yellowish spore masses or pustules commonly on the lower leaf surfaces. Each rust species is specific to a certain host genus or species and cannot spread to unrelated plants. Moderate infections will not harm plants, but can make plants unattractive. Heavily infected leaves may curl, wither and drop prematurely. Severely infected plants may be stunted. Rusts spread primarily via windblown spores.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Coneflower (Echinacea)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Coral bells, Alum root (Heuchera)

  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Cranesbill (Geranium)

  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Daffodil (Narcissus)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Daisy (Leucanthemum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Daylily (Hemerocallis)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Dead nettle (Lamium)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Evening primrose (Oenothera)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

False spirea (Astilbe)

  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Four-lined plant bug (Poecilocapsus lineatus)
    Adults are 1/4-1/3" long, and yellow to yellow-green with four longitudinal black lines down the wing covers, and black antennae. Nymphs are bright red-orange with black dots on the abdomen. Insect has a short lifecyle beginning in late April/early May. Adult activity outdoors is over by the end of spring. One generation produced annually.
  • Fusarium wilt (Fusarium species (H))
    Infected plants wilt and die. Foliage yellows, curls, wilts, then browns and dies. Lower foliage is usually affected first. In many hosts, symptoms may appear only on one side of the plant. If you take a cross-section of the basal stem, vascular tissues may be discolored and you may see brown rings or solid brown coloration, often from the soil line to shoots.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • Tobacco rattle (Tobacco rattle virus)
    Symptoms include mottling (blotchy light/dark discoloration of leaf tissue), yellow ring spots or line patterns, localized necrotic (dead) lesions, chlorotic spots or streaks or notched leaves. Plants infected at a young age may also exhibit a variety of leaf and stem deformities. This virus is spread primarily by stubby-root nematodes, a group of microscopic worm-like organisms. Nematodes feed on the roots of infected plants, then move to non-infected plants where subsequent feeding spreads the virus. TRV can also be spread mechanically with contaminated pruning tools and by grafting. This virus can also be found in the seeds of infected plants.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.

Feather reed grass (Calamagrostis)

  • Anthracnose (herbaceous) (Several)
    Symptoms typically appear as tan to brown spots or sunken lesions that may combine to form irregular, dark lesions that cause rapid blighting of leaves or stems. Depending on the fungus species and host plant species, foliage may also distort, turn yellow, wilt, drop prematurely or die. This may cause signficant plant losses if not diagnosed in the early stages of infection. Under wet conditions, these diseases can have multiple infection cycles during the growing season. Anthracnose fungi persist primarily in infected plant parts and crop debris.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Rusts (herbaceous) (Several)
    Symptoms of infection usually first appear as light-colored spots on upper leaf surfaces followed by dry, brown, orange, purple, reddish or yellowish spore masses or pustules commonly on the lower leaf surfaces. Each rust species is specific to a certain host genus or species and cannot spread to unrelated plants. Moderate infections will not harm plants, but can make plants unattractive. Heavily infected leaves may curl, wither and drop prematurely. Severely infected plants may be stunted. Rusts spread primarily via windblown spores.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Foamflower (Tiarella)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Fountain grass (Pennisetum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Fumitory (Corydalis)

  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Gayfeather (Liatris)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Globe thistle (Echinops)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Goblin flower (Gaillardia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Goldenrod (Solidago)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Hosta (Hosta)

  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Iris (Iris)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Jacob's ladder (Polemonium)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Lamb's ear, Betony (Stachys)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Lenten rose (Hellebore)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Leopard plant (Ligularia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Lily (Lilium)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Lily of the valley (Convallaria)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Anthracnose (herbaceous) (Several)
    Symptoms typically appear as tan to brown spots or sunken lesions that may combine to form irregular, dark lesions that cause rapid blighting of leaves or stems. Depending on the fungus species and host plant species, foliage may also distort, turn yellow, wilt, drop prematurely or die. This may cause signficant plant losses if not diagnosed in the early stages of infection. Under wet conditions, these diseases can have multiple infection cycles during the growing season. Anthracnose fungi persist primarily in infected plant parts and crop debris.
  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • Fusarium wilt (Fusarium species (H))
    Infected plants wilt and die. Foliage yellows, curls, wilts, then browns and dies. Lower foliage is usually affected first. In many hosts, symptoms may appear only on one side of the plant. If you take a cross-section of the basal stem, vascular tissues may be discolored and you may see brown rings or solid brown coloration, often from the soil line to shoots.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Southern blight (Sclerotium rolfsii)
    This disease is only active during hot weather. Plants may grow well in infested soil during most of the growing season and only be damaged during the hottest part of summer. Initial symptoms are yellowing or wilting of lower leaves, then basal stems decay, followed by the collapse of individual stems or entire plants. Inspection of the stem at the soil line reveals white mycelium (fungal strands) and small, tan spherical sclerotia (fungal survival structures) that resemble mustard seeds. Roots are unaffected. Decay of the stem at the soil line is common during hot, humid weather.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Lily turf (Liriope)

  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Lungwort (Pulmonaria)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Lupine (Lupinus)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Maiden grass, Eulalia (Miscanthus)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Meadow rue (Thalictrum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Monkshood (Aconitum)

  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cyclamen and Broad mites (Tarsonemidae family)
    Miniscule mites, often less than 1/80", are colorless or may have a pale brown tint. Can develop rapidly, with generation times completed in about 1 week. If temperature conditions are favorable, cyclamen mites can reproduce continually. Goes dormant in winter and reactivates in spring. Cyclamen and broad mites have different genera, but cause similar damage and are impossible to ID without high magnification. Broad mites are restricted to greenhouses in our area.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Four-lined plant bug (Poecilocapsus lineatus)
    Adults are 1/4-1/3" long, and yellow to yellow-green with four longitudinal black lines down the wing covers, and black antennae. Nymphs are bright red-orange with black dots on the abdomen. Insect has a short lifecyle beginning in late April/early May. Adult activity outdoors is over by the end of spring. One generation produced annually.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora blight (herbaceous) (Phytophthora species (H))
    Symptoms appear as dark brown to black leathery tissue on plant parts, but commonly the lower halves of young shoots, stems or the bases of blighted leaves. Shoots may wilt and collapse. Severe infection may affect the entire crown. If you cut into the stem, vascular tissues show brown, olive green, reddish or dark streaking. Phytophthora is a 'water mold' and it is favored by frequent irrigation and wet, slow draining soils. Saturated soils encourage spore production, causing more severe disease.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • Verticillium wilt (herbaceous) (Verticillium species (H))
    Infected plants wilt, turn yellow, then brown-progressing upwards from the base to the tip of the plant or branch, and then they die. Browning of older leaves while younger leaves remain green is also characteristic. If you cut into the stem, vascular tissues show discoloration as brown, olive green, reddish or dark streaking. Verticillium usually infects during cool conditions, but damage may not become apparent until warm weather and the plant is stressed. It is favored by droughty conditions.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Obedient plant (Physostegia)

  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Phlox (Phlox)

  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Pigsqueak (Bergenia)

  • Anthracnose (herbaceous) (Several)
    Symptoms typically appear as tan to brown spots or sunken lesions that may combine to form irregular, dark lesions that cause rapid blighting of leaves or stems. Depending on the fungus species and host plant species, foliage may also distort, turn yellow, wilt, drop prematurely or die. This may cause signficant plant losses if not diagnosed in the early stages of infection. Under wet conditions, these diseases can have multiple infection cycles during the growing season. Anthracnose fungi persist primarily in infected plant parts and crop debris.
  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Slug (Order Sytlomatophora)
    Garden slugs are terrestrial mollusks, essentially snails without shells. As they move, they coat surfaces with a silvery, slimy substance. Most feed at night or during dark, cloudy days. Trails and feeding injuries are usually noticed before the slug itself. Slugs overwinter either as adults or as eggs. They become active during the first warm days of spring, and thrive under cool, damp conditions. Populations will be high during/following damp, rainy weather, and will almost disappear during dry periods. Slugs cannot survive direct sunlight. Rock walls, boards, pots and plant debris, as well as shaded flower beds and heavily mulched gardens, serve as ideal daytime resting sites.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Poppy (Papaver)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Prickly pear cactus (Opuntia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Red hot poker (Kniphofia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Rock cress (Aubrieta)

  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Rose mallow (Hibiscus)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Soapwort (Saponaria)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Solomon's seal (Polygonatum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Speedwell (Veronica)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Spurge (Euphorbia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

St. John's wort (Hypericum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Stokes' aster (Stokesia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Stonecrop (Sedum)

  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Sweet Flag (Acorus)

  • Anthracnose (herbaceous) (Several)
    Symptoms typically appear as tan to brown spots or sunken lesions that may combine to form irregular, dark lesions that cause rapid blighting of leaves or stems. Depending on the fungus species and host plant species, foliage may also distort, turn yellow, wilt, drop prematurely or die. This may cause signficant plant losses if not diagnosed in the early stages of infection. Under wet conditions, these diseases can have multiple infection cycles during the growing season. Anthracnose fungi persist primarily in infected plant parts and crop debris.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.

Sweet woodruff (Galium)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Switchgrass (Panicum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Tansy, Feverfew (Tanacetum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Tickweed (Coreopsis)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Aster leafhopper (Macrosteles quadrilineatus)
    Adult aster leafhoppers small (1/8" long), yellow-green, wedge-shaped insects with black spots on their heads. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings.
  • Aster yellows ()
    Causes general yellowing and stunting of host plant. Symptoms are often mistaken for herbicide damage. Infected plants are stunted and twisted, with red or yellow foliage, and often sterile. Normally colored flower parts may remain green with puckered and distorted petals/sepals. In purple coneflower, secondary flower heads (often in a cluster) may emerge from primary flower heads. In marigolds, flowers are often leafy and a muddy green-orange color. Perennials infected with aster yellows generally die within the first season of infection. Aster yellows is a phytoplasma disease spread by the aster leafhopper.
  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Coreopsis beetle (Calligrapha californica coreopsivora)
    Adults are 6-7mm long and have brownish-black rotund bodies with yellowish-orange parallel stripes on the wing-covers.
  • Cucumber beetle (Spotted/Striped) (Chrysomelidae family (CB))
    Larvae are pale-colored and wormlike with brown heads. Adult spotted cucumber beetles are about 1/4" long, with shiny black heads and greenish-yellow with 12 black spots on their backs. Adult striped cucumber beetles are about 1/4" long, with shiny black heads and are yellowish-orange with 3 black stripes. There may be 1-2 generations of each type of cucumber beetle per year.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Downy mildew (herbaceous) (Several)
    Early symptoms appear as irregular, light green or yellow angular patches on upper leaf surfaces. Lesions may also be purplish red to dark brown. Under high humidity, downy mildews form fluffy or fuzzy (downy) areas of spores on the undersides of leaves. Under magnification, the downy areas look like very small bunches of branched hairs. Older leaves toward the bottom of plants are usually infected first and wither and brown as the disease proceeds up the stem.
  • Four-lined plant bug (Poecilocapsus lineatus)
    Adults are 1/4-1/3" long, and yellow to yellow-green with four longitudinal black lines down the wing covers, and black antennae. Nymphs are bright red-orange with black dots on the abdomen. Insect has a short lifecyle beginning in late April/early May. Adult activity outdoors is over by the end of spring. One generation produced annually.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Rhizoctonia web blight (Rhizoctonia species (H))
    This disease is favored by high temperatures and high humidity, especially in the greenhouse setting. Symptoms appear as irregular, brown spots which can form anywhere on foliage or stems. In high humidity, web-like brown mycelium can cover infected portions of the plant host. Rhizoctonia is a soil-borne pathogen.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.
  • Woolly aphids (Several)
    Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.

Various ferns (Adiantum, Asplenium, Blechnum, Dryopteris, Gymnocarpium, Polystichum, etc.) (Ferns)

  • Animal damage ()
    Animals that do the most damage to herbaceous plants include: deer, rabbits and woodchucks. Deer damage is distinctive because deer only have teeth on their lower jaws, so when they bite down, they must tear the plant to pull off leaves. Thus, deer damage to plants is rough or shredded-looking. It may also be several feet off of the ground. Plus, if a large amount of plant material is damaged overnight, you should suspect deer. Rabbit damage looks like someone used a pruner to cut the plant off at a clean, 45-degree angle. Woodchucks will mow down plants, or sometimes just nibble on succulent material. They are diurnal, so keep on the lookout.
  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Slug (Order Sytlomatophora)
    Garden slugs are terrestrial mollusks, essentially snails without shells. As they move, they coat surfaces with a silvery, slimy substance. Most feed at night or during dark, cloudy days. Trails and feeding injuries are usually noticed before the slug itself. Slugs overwinter either as adults or as eggs. They become active during the first warm days of spring, and thrive under cool, damp conditions. Populations will be high during/following damp, rainy weather, and will almost disappear during dry periods. Slugs cannot survive direct sunlight. Rock walls, boards, pots and plant debris, as well as shaded flower beds and heavily mulched gardens, serve as ideal daytime resting sites.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Thielaviopsis rot (herbaceous-root, stem or crown) (Thielaviopsis basicola (H))
    Aboveground symptoms include stunting, chlorosis and even plant death. Infected roots decay and thicken. They may be very black in color in mixes containing soil. Belowground stems may develop black, longitudinal cracks. Basal stem and root lesions are drier than those caused by Rhizoctonia.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • White mold (Sclerotinia stem rot) (Sclerotinia species)
    Symptoms vary with the plant host and can lead to crown and stem cankers, root rots, wilts, damping-off of seedlings, and blossom and fruit rots. Plants can wilt rapidly as a result of stem-girdling cankers at or near the soil line. Brown spots can appear on flower petals and buds. Cottony masses of fungal threads (hyphae) may appear on stems or on nearby soil. Hard, irregularly-shaped masses (sclerotia) develop within or on the surface of infected plants. The sclerotia are white at first and then turn dark brown or black when mature. This disease favors cool wet springs and fall weather. Spores are dispersed primarily by wind, watersplash and insects.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Wandflower (Gaura)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Wormwood (Artemisia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Yarrow (Achillea)

  • Alternaria leaf spot (Alternaria species)
    Causes numerous dark brown to black spots, which may develop in concentric rings or appear targetlike, on infected leaves. The plant may appear chlorotic and leaves may dry or drop prematurely. Stem lesions or cankers may develop, sometimes girdling and killing stems. Alternaria species persist in infected crops, seeds and plant debris. Spores are carried mainly by the wind, but can also be spread by watersplash to neighboring plants.
  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Crown gall (herbaceous) (Agrobacterium tumefaciens (H))
    Infected plants exhibit distorted growth or galls on the lower stem. To identify, crown gall surface tissue is the same color and as firm as healthy plant tissue; and swellings cannot be rubbed off of the plant. Roots may appear gnarled, stunted or hairy with mostly small rootlets. Symptomatic plants may also be chlorotic, distorted, grow slowly, have small leaves, and because they're under stress, may be more susceptible to drought and other problems. Galls can crack and become infected with secondary pathogens. Herbaceous plants may be more seriously affected and possibly killed.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • Powdery mildew (herbaceous) (Several)
    Symptoms appear as a white powdery coating on surfaces of leaves, buds, twigs, and stems. Fungi can overwinter as spores on leaf litter or in buds. Spores spread via air currents and rainsplash. Older leaves usually show symptoms first. The disease's impact varies depending on host. Infected leaves may distort, discolor, dry and drop prematurely.
  • Pythium rot (root, stem or crown-herbaceous) (Pythium species (H))
    First symptoms are yellow, stunted or wilted plants. Pythium infects young tissue, often root tips, and causes a dark brown to black wet rot that softens and disintegrates tissue. This disease commonly attacks below the soil surface from root tips to primary roots and sometimes to the base of the plant, and is favored by wet, poorly drained conditions.
  • Rhizoctonia rot (root, stem or crown-herbaceous) (Rhizoctonia species (H))
    Symptoms include wilting and death, especially of seedlings (damping off). Moist brown lesions commonly form at the base of infected petioles or on lower stems, usually at the soil line. Crown areas decay, and roots are also sometimes infected and become dark and decayed, especially in peat-containing mixes. Rhizoctonia root rot is favored by relatively high temperatures and intermediate moisture, neither too wet nor too dry. It persists in growing media and is common in many soils.
  • Rhizoctonia web blight (Rhizoctonia species (H))
    This disease is favored by high temperatures and high humidity, especially in the greenhouse setting. Symptoms appear as irregular, brown spots which can form anywhere on foliage or stems. In high humidity, web-like brown mycelium can cover infected portions of the plant host. Rhizoctonia is a soil-borne pathogen.
  • Rusts (herbaceous) (Several)
    Symptoms of infection usually first appear as light-colored spots on upper leaf surfaces followed by dry, brown, orange, purple, reddish or yellowish spore masses or pustules commonly on the lower leaf surfaces. Each rust species is specific to a certain host genus or species and cannot spread to unrelated plants. Moderate infections will not harm plants, but can make plants unattractive. Heavily infected leaves may curl, wither and drop prematurely. Severely infected plants may be stunted. Rusts spread primarily via windblown spores.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.

cinquefoil (Potentilla)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Woody Ornamentals

Lavender (Lavandula)

  • Woolly aphids (Several)
    Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.

Rhododendron, Azalea (Rhododendron)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Russian sage (Perovskia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Sage (Salvia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Thyme (Thymus)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Woody Ornamentals-Conifer

Arborvitae (Thuja)

  • Arborvitae leafminer (Argyresthia species)
    Mature larvae are approximately 6 mm long with greenish brown bodies and a black head. Adults are silvery gray moths.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Shothole borer (Scolytus rugulosus)
    Borers are small 1/10th inch gray-black beetles.
  • Spruce spider mite (Oligonychus ununguis)
    Mites are 0.5 mm long with eight legs. Green or dark red in color.

Boxwood (Buxus)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (woody plants) (Cylindrocladium species)
    Root infections are characterized by many dark brown to black lesions often with longitudinal cracks. Severe root disease leads to stunting, wilting, yellowing and death. Stem infections of both conifers and broadleaves arise at the leaf bases and may girdle small stems. Diseased conifer needles turn yellow or red-brown. Dark lesions form in the leaves of broadleaf plants. Leaf blight leads to defoliation.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Douglas fir (Pseudotsuga)

  • Cooley spruce gall adelgid (Adelges cooleyi)
    Closely resembles aphids. Adelgids are 1 mm long, and dark brown to black in color. Adults secrete white curled waxy strands to cover their bodies.
  • Eastern spruce gall adelgid (Adelges abietis)
    Closely resembles aphids with a body that is 1mm long, and dark brown to black in color. Adults secrete white curled waxy strands to cover their bodies.
  • White-marked tussock moth (Orygia leucostigma)
    Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.
  • Woolly adelgids (Several)
    A family of woolly aphids that are associated with conifers. These are not true aphids but similar to woolly aphids in that their bodies are covered in white, cottony, wax-like threads that cause them to appear wooly.
  • Woolly aphids (Several)
    Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.

Fir (Abies)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Balsam gall midge (Paradiplosis tumifex)
    Insects are tiny delicate flies which deposit their eggs on the terminal buds of conifers. Upon hatching tiny white larvae migrate to the bases of newly forming needles and burrow into needle tissue.
  • Balsam twig aphid (Mindarus abietus)
    Mature aphids are bluish gray and approximately 1.8 mm long
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cytospora canker (Cytospora species)
    A stem and branch disorder affecting many different types of conifers. In Wisconsin, Colorado Blue Spruce is the main species that is affected.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Scorch ()
    The primary symptom of scorch is the browning of leaf edges or needles. Sometimes there will be a distinct yellow band between the leaf edges and the green inner leaf. On conifers, especially spruce, affected needles will turn reddish-purple then brown. Scorch itself is a symptom and not the root cause of the problem. Woody species often affected by scorch include: Acer, Abies, Fraxinus, Pinus, Quercus and Tilia. Scorch may not affect the whole plant uniformly. It is not generally fatal. However, if extensive damage is present by mid-summer, the plant's ability to make food will be reduced and it may be more susceptible to winter damage. Scorch usually results from the following: insufficient water (due to drought, improper siting, impaired root systems); a response to an undesirable soil or air constituent (salt accumulation or atmospheric chemicals); or a response to fungal or bacteria pathogens.
  • Seasonal Needle Drop ()
    Evergreen needles naturally discolor and drop off after one or more years on the plant, and interior needles are affected. Seasonal needle drop may be gradual or all at once and can be mistaken for disease or insect damage. Each species tends to keep their needles for a specific period of time, varying slightly between trees and from year to year. Pinus strobus is the most dramatically affected. Third year needles turn yellow throughout the tree and will usually drop by winter. It may look as if yellowed needles outnumber green ones, but this is natural. P. nigra and P. sylvestris usually retain needles for three years and drop them in their fourth year. Thuja occidentalis usually turn brown rather than yellow and remain attached much longer than mature pine needles. Taxus spp. needles turn yellow and drop in late spring or early summer of their third year. Abies and Picea spp. yellow and drop with age, but because of their branch arrangement, it's often difficult to tell unless you part the branches to look at the interior.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Spruce spider mite (Oligonychus ununguis)
    Mites are 0.5 mm long with eight legs. Green or dark red in color.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Swiss needlecast (Phaeocryptopus gaeumannii)
    Infected needles of Douglas fir become discolored, turning a blotchy yellow-green or yellow, and then browning from the tips. Older needles are more severely affected than younger needles. Brown needles drop prematurely, leaving twigs with only the newest growth. Using a hand lens, small, black reproductive structures of the Swiss needlecast fungus can be seen in two diffuse bands on the undersurface of infected needles.
  • White pine weevil (Pissodes strobi)
    Adult weevils are 6 mm long with a long snout and oval body which is brown with brown and white spots on the back. There may also be some lateral die back due to larval feeding.
  • White-marked tussock moth (Orygia leucostigma)
    Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.
  • Woolly adelgids (Several)
    A family of woolly aphids that are associated with conifers. These are not true aphids but similar to woolly aphids in that their bodies are covered in white, cottony, wax-like threads that cause them to appear wooly.

Hemlock (Tsuga)

  • Cytospora canker (Cytospora species)
    A stem and branch disorder affecting many different types of conifers. In Wisconsin, Colorado Blue Spruce is the main species that is affected.

Juniper (Juniperus)

  • Cedar-rosaceous rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
    On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance.
  • Juniper scale (Carulaspis juniperi)
    Both male and female scales are creamy white. Females are 1.5 mm in diameter while male juniper scale is slightly smaller and oval in shape.
  • Phomopsis twig blight (Phomopsis juniperovora)
    A shoot tip disorder of Junipers.
  • Shothole borer (Scolytus rugulosus)
    Borers are small 1/10th inch gray-black beetles.

Pine (Pinus)

  • Brown spot (Mycosphaerella dearnessii)
    Similar to Lophodermium needlecast. This disease first appears as bar like gray-black spots which turn brown with yellow margins before they are detected. Later the entire needle turns yellow, then brown and may fall off. Older trees show most infection at ground level, with the disease progressing upward. Older needles on the branch are most likely to show symptoms. Infection by Brown Spot most often occurs in August and September. Needles then die back and turn brown.
  • Cytospora canker (Cytospora species)
    A stem and branch disorder affecting many different types of conifers. In Wisconsin, Colorado Blue Spruce is the main species that is affected.
  • Diplodia shoot blight & canker (Diplodia pinea)
    A shoot tip disorder that can affect a number of pine species.
  • Dothistroma needle blight (Dothistroma septosporum)
    Dothistroma needle blight first appears as dark green, water-soaked spots on the needles. The spots become tan, yellow, or reddish-brown, and may encircle the needles to form bands. The tip of the needle beyond the band eventually dies leaving the base of the needle alive and green. Young trees are more likely to suffer damage than older trees. Seedlings (<1 yr. old) can be killed within a year after infection.
  • Eastern pine shoot borer (Eucosoma gloriola)
    Larvae up to 13 mm in length are off white to gray with yellowish brown heads. Adults have a copper red color with two gray bands on the forewings.
  • European pine sawfly (Neodiprion sertifer)
    Larvae are gray green with black heads and legs. They have a light green stripe down the back and two light green and one dark green to black stripe on each side. Larvae are 18 - 25 mm long when mature.
  • European pine shoot moth (Rhyacionia buoliana)
    Larvae are brown with a black head and legs and 18 mm long when mature. Adults are rusty red moths.
  • Introduced pine sawfly (Diprion similis)
    Larvae have a black head and a yellow-green body with a black double stripe down the back and many yellow spots. Approximately 24 mm in length with three pairs of thoracic legs and 8 pairs of abdominal prolegs. Adult sawflies are 4-7 mm long.
  • Lophodermium needlecast (Lophodermium)
    Similar to Brown Spot. First appears as bar like gray-black spots turning brown with yellow margins before they are detected. Later the entire needle turns yellow, then brown and may fall off. Older trees show most infection at ground level, with the disease progressing upward. Older needles on the branch are most likely to show symptoms. Damage is most often noticed in the Spring.
  • Pine needle miner (Zelleria haimbachi)
    Adult female scales are white, teardrop shaped and 2.5 - 3 mm long.
  • Pine needle scale (Chionaspis pinifoliae)
    Crawlers are amber colored. Adult scale is gray to black.
  • Pine tortoise scale (Toumeyella parvicornis)
    Females are reddish brown, 4-7mm long and convex.
  • Redheaded pine sawfly (Neodiprion lecontei)
    Larvae are up to 30 mm long with reddish brown heads and yellow bodies with 6 rows of irregular black spots. Adults are brownish and wasp like.
  • Shothole borer (Scolytus rugulosus)
    Borers are small 1/10th inch gray-black beetles.
  • White pine weevil (Pissodes strobi)
    Adult weevils are 6 mm long with a long snout and oval body which is brown with brown and white spots on the back. There may also be some lateral die back due to larval feeding.
  • Woolly adelgids (Several)
    A family of woolly aphids that are associated with conifers. These are not true aphids but similar to woolly aphids in that their bodies are covered in white, cottony, wax-like threads that cause them to appear wooly.
  • Woolly aphids (Several)
    Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.
  • Zimmerman pine moth complex (Dioryctria zimmermani)
    Mature larvae are up to 25 mm long, dirty white and occasionally have pale pink or pale green coloration. Bodies have black spots on the abdomen and their heads are also black. Adults are moths.

Spruce (Picea)

  • Cooley spruce gall adelgid (Adelges cooleyi)
    Closely resembles aphids. Adelgids are 1 mm long, and dark brown to black in color. Adults secrete white curled waxy strands to cover their bodies.
  • Cytospora canker (Cytospora species)
    A stem and branch disorder affecting many different types of conifers. In Wisconsin, Colorado Blue Spruce is the main species that is affected.
  • Eastern spruce gall adelgid (Adelges abietis)
    Closely resembles aphids with a body that is 1mm long, and dark brown to black in color. Adults secrete white curled waxy strands to cover their bodies.
  • Rhizosphaera needlecast (Rhizosphaera kalkhoffii)
    The first noticeable sign of Rhizosphaera needlecast is a loss of the inner-most needles on the lower branches of spruce trees. Often the youngest needles remain healthy. If your tree has this pattern of needle loss, use a 10X hand lens to observe the shed needles. If Rhizosphaera needlecast is the problem, you should be able to see rows of small black dots erupting through the surface of the needle. These black dots are fruiting bodies of the fungus that causes the disease and are diagnostic.
  • Spruce needle miner (Endothenia albolineana)
    Larvae are light greenish brown caterpillars with a dark head and about 10 mm in length.
  • Spruce spider mite (Oligonychus ununguis)
    Mites are 0.5 mm long with eight legs. Green or dark red in color.
  • White pine weevil (Pissodes strobi)
    Adult weevils are 6 mm long with a long snout and oval body which is brown with brown and white spots on the back. There may also be some lateral die back due to larval feeding.
  • Woolly aphids (Several)
    Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.

Yew (Taxus)

  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Taxus mealybug (Phenacoccus acericola)
    A small soft bodied insect covered with fine whitish wax, similar in appearance to soft scale.

Woody Ornamentals-Deciduous-Shrub

Barberry (Berberis)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Bacterial leaf spot & twig blight (Pseudomonas syringae pv. Syringae)
    Initial symptoms of bacterial blight may include dark brown necrotic (dead) leaf spots with yellow margins. If leaf spots develop before leaves are fully expanded, leaf curling and twisting may result. More advanced symptoms include necrotic blotches starting at the leaf margins and advancing inward, as well as black streaking on twigs. In its' most severe form, bacterial blight can result in the death of branch tips, leaves and blossoms.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cucumber mosaic (Cucumber mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Viruses can retard plant growth and change the appearance of foliage, flowers and fruits. Virus-infected leaves can become spotted, streaked or mottled; they may be distorted or stunted. Veins may lose their color or develop outgrowths. Flowers can be dwarfed, deformed, streaked, faded, or they can remain green and develop into leaf-like structures.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Powdery mildew (woody plants) (Several)
    The upper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has h pper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has sprinkled them with talcum powder or powdered sugar.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Southern blight (Sclerotium rolfsii)
    This disease is only active during hot weather. Plants may grow well in infested soil during most of the growing season and only be damaged during the hottest part of summer. Initial symptoms are yellowing or wilting of lower leaves, then basal stems decay, followed by the collapse of individual stems or entire plants. Inspection of the stem at the soil line reveals white mycelium (fungal strands) and small, tan spherical sclerotia (fungal survival structures) that resemble mustard seeds. Roots are unaffected. Decay of the stem at the soil line is common during hot, humid weather.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.

Blue mist spirea (Caryopteris)

  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Four-lined plant bug (Poecilocapsus lineatus)
    Adults are 1/4-1/3" long, and yellow to yellow-green with four longitudinal black lines down the wing covers, and black antennae. Nymphs are bright red-orange with black dots on the abdomen. Insect has a short lifecyle beginning in late April/early May. Adult activity outdoors is over by the end of spring. One generation produced annually.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Manganese deficiency - woody plants ()
    Manganese (Mn) deficiency is most likely to occur in neutral to high pH soils that are also high in organic matter. This is common in the red soils of eastern Wisconsin, especially in low-lying, poorly drained areas, and on burned-over organic soils. Symptoms of Mn deficiency in broadleaf trees/shrubs manifest as interveinal chlorosis sometimes worsening to necrosis, undersized leaves, or leaves with curly, wavy or crinkled leaf margins. Symptoms appear on new growth first. Acer rubrum is particularly susceptible to this condition. In conifers, Mn deficiency symptoms closely resemble those of iron (Fe) deficiency: chlorotic and stunted new growth, with the older growth remaining green. Symptoms are more likely to appear on drought-stressed or acid-loving plants.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Butterfly bush (Buddleia)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cucumber mosaic (Cucumber mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Viruses can retard plant growth and change the appearance of foliage, flowers and fruits. Virus-infected leaves can become spotted, streaked or mottled; they may be distorted or stunted. Veins may lose their color or develop outgrowths. Flowers can be dwarfed, deformed, streaked, faded, or they can remain green and develop into leaf-like structures.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Earwig (Forficula auricularia)
    Adults are about 1/2" long with prominent pincers on their hind ends, and reddish brown with lighter-colored, short wing covers on the thorax. Earwigs overwinter in the adult stage. Females lay eggs twice in a season, but there is only 1 generation per year. Foraging occurs at night, with movement to dark, sheltered areas during the day.
  • Four-lined plant bug (Poecilocapsus lineatus)
    Adults are 1/4-1/3" long, and yellow to yellow-green with four longitudinal black lines down the wing covers, and black antennae. Nymphs are bright red-orange with black dots on the abdomen. Insect has a short lifecyle beginning in late April/early May. Adult activity outdoors is over by the end of spring. One generation produced annually.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Manganese deficiency - woody plants ()
    Manganese (Mn) deficiency is most likely to occur in neutral to high pH soils that are also high in organic matter. This is common in the red soils of eastern Wisconsin, especially in low-lying, poorly drained areas, and on burned-over organic soils. Symptoms of Mn deficiency in broadleaf trees/shrubs manifest as interveinal chlorosis sometimes worsening to necrosis, undersized leaves, or leaves with curly, wavy or crinkled leaf margins. Symptoms appear on new growth first. Acer rubrum is particularly susceptible to this condition. In conifers, Mn deficiency symptoms closely resemble those of iron (Fe) deficiency: chlorotic and stunted new growth, with the older growth remaining green. Symptoms are more likely to appear on drought-stressed or acid-loving plants.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Root rot (woody plants) (Cylindrocladium species)
    Root infections are characterized by many dark brown to black lesions often with longitudinal cracks. Severe root disease leads to stunting, wilting, yellowing and death. Stem infections of both conifers and broadleaves arise at the leaf bases and may girdle small stems. Diseased conifer needles turn yellow or red-brown. Dark lesions form in the leaves of broadleaf plants. Leaf blight leads to defoliation.
  • Scorch ()
    The primary symptom of scorch is the browning of leaf edges or needles. Sometimes there will be a distinct yellow band between the leaf edges and the green inner leaf. On conifers, especially spruce, affected needles will turn reddish-purple then brown. Scorch itself is a symptom and not the root cause of the problem. Woody species often affected by scorch include: Acer, Abies, Fraxinus, Pinus, Quercus and Tilia. Scorch may not affect the whole plant uniformly. It is not generally fatal. However, if extensive damage is present by mid-summer, the plant's ability to make food will be reduced and it may be more susceptible to winter damage. Scorch usually results from the following: insufficient water (due to drought, improper siting, impaired root systems); a response to an undesirable soil or air constituent (salt accumulation or atmospheric chemicals); or a response to fungal or bacteria pathogens.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Southern blight (Sclerotium rolfsii)
    This disease is only active during hot weather. Plants may grow well in infested soil during most of the growing season and only be damaged during the hottest part of summer. Initial symptoms are yellowing or wilting of lower leaves, then basal stems decay, followed by the collapse of individual stems or entire plants. Inspection of the stem at the soil line reveals white mycelium (fungal strands) and small, tan spherical sclerotia (fungal survival structures) that resemble mustard seeds. Roots are unaffected. Decay of the stem at the soil line is common during hot, humid weather.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Cotoneaster (Cotoneaster)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • Cedar-rosaceous rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
    On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Fire blight (Erwinia amylovora)
    Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • Leafhoppers (Several)
    3-15 mm in length, wedge shaped with wings that peak over their backs. Nymphs are wingless but active and move readily when disturbed. Adults are winged and fly readily when disturbed.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Pearslug sawfly (Caliroa cerasi)
    Adults are small, stout, shiny black wasps about 1/3" long that emerge in late June or early July. Eggs are inserted one by one in circular slits on the upper surfaces of leaves and hatch about 2 weeks later. Larvae are shiny, slimy, swollen at the head end, and range in color from olive green to orangeish-green. Full grown larvae leave plants to pupate in the soil and may emerge as adults in about 2 more weeks to produce a 2nd generation. Some remain dormant until the following spring.
  • Pine needle scale (Chionaspis pinifoliae)
    Crawlers are amber colored. Adult scale is gray to black.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Rhizoctonia web blight (Rhizoctonia species (H))
    This disease is favored by high temperatures and high humidity, especially in the greenhouse setting. Symptoms appear as irregular, brown spots which can form anywhere on foliage or stems. In high humidity, web-like brown mycelium can cover infected portions of the plant host. Rhizoctonia is a soil-borne pathogen.
  • Root rot (Fusarium species (W))
    Symptoms include stunting, chlorosis, root necrosis and death of woody plants. Symptoms are dependent on cultural practices and the local environment.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Rhizoctonia species (W))
    Symptoms on the above ground parts of larger plants include necrotic spots and blotches on the leaves, shoot blight and dieback.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Scab (Venturia inaequalis)
    Scab lesions (diseased areas) are often first noticed on leaves, where they most commonly occur on the upper leaf surface. Fruits are also very susceptible to infection. Lesions on both leaves and fruits are roughly circular with feathery edges, and have an olive green to black color. They can be as small as the size of a pinhead or as large a 1/2 inch in diameter. When the disease is severe, lesions can merge and cover a large portion of the leaf or fruit surface. Defoliation of the tree often follows.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • Woolly aphids (Several)
    Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.

Daphne (Daphne)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Dogwood (Cornus)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Bacterial leaf spot & twig blight (Pseudomonas syringae pv. Syringae)
    Initial symptoms of bacterial blight may include dark brown necrotic (dead) leaf spots with yellow margins. If leaf spots develop before leaves are fully expanded, leaf curling and twisting may result. More advanced symptoms include necrotic blotches starting at the leaf margins and advancing inward, as well as black streaking on twigs. In its' most severe form, bacterial blight can result in the death of branch tips, leaves and blossoms.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cottony maple scale (Pulvinaria innumerabilis)
    Flat and pale brown to dark brown, Scales form protruding white egg sacs which are over 1/4th of an inch when the egg mass swells.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Dogwood sawfly (Macremphytus tarsatus)
    Early stage larvae are white and powdery looking, but develop distinct spots in their last larval instar. They can reach 1" long. Adults emerge from May to July and insert up to 100 eggs at a time into leaf tissue. There is one generation per year.
  • Flea beetle (Chrysomelidae family)
    Flea beetles are among the smallest of the leaf beetles, typically smaller than 1/6" long. They usually possess large rear legs used for jumping. Several species are found in Wisconsin.
  • Four-lined plant bug (Poecilocapsus lineatus)
    Adults are 1/4-1/3" long, and yellow to yellow-green with four longitudinal black lines down the wing covers, and black antennae. Nymphs are bright red-orange with black dots on the abdomen. Insect has a short lifecyle beginning in late April/early May. Adult activity outdoors is over by the end of spring. One generation produced annually.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Leafhoppers (Several)
    3-15 mm in length, wedge shaped with wings that peak over their backs. Nymphs are wingless but active and move readily when disturbed. Adults are winged and fly readily when disturbed.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Powdery mildew (woody plants) (Several)
    The upper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has h pper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has sprinkled them with talcum powder or powdered sugar.
  • Root rot (Fusarium species (W))
    Symptoms include stunting, chlorosis, root necrosis and death of woody plants. Symptoms are dependent on cultural practices and the local environment.
  • Root rot (woody plants) (Cylindrocladium species)
    Root infections are characterized by many dark brown to black lesions often with longitudinal cracks. Severe root disease leads to stunting, wilting, yellowing and death. Stem infections of both conifers and broadleaves arise at the leaf bases and may girdle small stems. Diseased conifer needles turn yellow or red-brown. Dark lesions form in the leaves of broadleaf plants. Leaf blight leads to defoliation.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Septoria leaf spot (woody plants) (Septoria species (W))
    Symptoms of Septoria leaf spot first appear at the base of affected plants, where small spots (approximately 1/4 inch diameter) appear on leaves and stems. These spots typically have a whitish center and a dark border. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Septoria leaf spot can lead to total defoliation of lower leaves and even the death of an infected plant.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Southern blight (Sclerotium rolfsii)
    This disease is only active during hot weather. Plants may grow well in infested soil during most of the growing season and only be damaged during the hottest part of summer. Initial symptoms are yellowing or wilting of lower leaves, then basal stems decay, followed by the collapse of individual stems or entire plants. Inspection of the stem at the soil line reveals white mycelium (fungal strands) and small, tan spherical sclerotia (fungal survival structures) that resemble mustard seeds. Roots are unaffected. Decay of the stem at the soil line is common during hot, humid weather.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Taxus mealybug (Phenacoccus acericola)
    A small soft bodied insect covered with fine whitish wax, similar in appearance to soft scale.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.

Euonymus (Euonymus)

  • Black vine weevil (Otiorhynchus sulcatus)
    Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 7-9 mm long, black with gold flecks. Insects are nocturnal, so scouting should occur at night.
  • Euonymus caterpillar (Yponomeuta cagnagella)
    Larvae are light greenish yellow in color with two sets of black spots on each body segment. Fully grown larvae reach 20mm in length.
  • Euonymus scale (Unaspis euonymi)
    Adult female scales have a dark brown oyster shaped cover about 3 mm long and are usually found on twigs. Male scales are smaller, fuzzy white, elongated and commonly found on foliage.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.

Forsythia (Forsythia)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Forsythia (Forsythia)

  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.

Heath (Erica)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Honeysuckle (Lonicera)

  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Lilac (Syringa)

  • Ash Yellows/Lilac Witches Broom (Candidatus Phytoplasma faxini)
    Ash yellows is a chronic, systemic disease of ash trees caused by a bacteria-like organism (Phytoplasma). The organism that causes ash yellows also causes a disease called lilac witches’-broom. The ash yellows phytoplasma is thought to be spread primarily through the feeding activity of leafhopper insects.
  • Ash-Lilac Borer (Clearwing Moth) (Podosesia syringae)
    Larvae are creamy white grubs with small dark heads and small prolegs on the abdomen with hook-like crochets at the tip.
  • Bacterial leaf spot & twig blight (Pseudomonas syringae pv. Syringae)
    Initial symptoms of bacterial blight may include dark brown necrotic (dead) leaf spots with yellow margins. If leaf spots develop before leaves are fully expanded, leaf curling and twisting may result. More advanced symptoms include necrotic blotches starting at the leaf margins and advancing inward, as well as black streaking on twigs. In its' most severe form, bacterial blight can result in the death of branch tips, leaves and blossoms.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Privet (Ligustrum)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Privet (Ligustrum)

  • Privet thrips (Dendrothrips ornatus)
    Adults are generally brown with thin light bands on each abdominal segment. Heavy infestations will cause leaves to become silvery in color.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Quince (Chaenomeles)

  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • Cedar-rosaceous rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
    On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Fire blight (Erwinia amylovora)
    Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Tarnished plant bug (Lygus lineolaris)
    Adults are 1/4" long, generally oval and about twice as long as wide. They are usually brownish with some yellow and reddish markings. Insect color tends to darken with age. Nymphs are more rounded, yellowish green to dark green, and often have dark spots. Adults overwinter in sheltered sites and become active in early spring. Several generations are produced annually.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Rhododendron (Rhododendron)

  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Rose (Rosa)

  • Fire blight (Erwinia amylovora)
    Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Rose of Sharon (Hibiscus)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Shrubby cinquefoil (Potentilla)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

Smoketree (Cotinus)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Peachtree borer (Synanthedon exitiosa)
    Larvae are creamy white with a reddish brown head.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Spiraea (Spiraea)

  • Fire blight (Erwinia amylovora)
    Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Sumac (Rhus)

  • Cottony maple scale (Pulvinaria innumerabilis)
    Flat and pale brown to dark brown, Scales form protruding white egg sacs which are over 1/4th of an inch when the egg mass swells.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Viburnum (Viburnum)

  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
  • Viburnum crown borer (Synanthedon viburni)
    Adults of both species are day flying moths that mimic the flight and appearance of wasps. They are bluish black with yellow markings, clear wings and a wingspan of 3/4 inch. Larvae are pinkish white caterpillars with reddish brown heads. During late and June and July, adults emerge from infested plants and deposit eggs on bark near wound sites. Larvae tunnel in the bark and cambium but do not enter the wood. Over time this will cause distortions and swellings on the main stems and branches.

Weigela (Weigela)

  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Woody Ornamentals-Deciduous-Tree

Ash (Fraxinus)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Ash Yellows/Lilac Witches Broom (Candidatus Phytoplasma faxini)
    Ash yellows is a chronic, systemic disease of ash trees caused by a bacteria-like organism (Phytoplasma). The organism that causes ash yellows also causes a disease called lilac witches’-broom. The ash yellows phytoplasma is thought to be spread primarily through the feeding activity of leafhopper insects.
  • Ash flower gall mite (Eriophyes fraxiniflora)
    Adult gall mites are carrot shaped with two pairs of legs but not easily visible without a microscope.
  • Ash plantbug (Tropidosteptes amoenus)
    Yellow or brown to black in color with yellow to pink markings with a length of 5-6 mm.
  • Ash-Lilac Borer (Clearwing Moth) (Podosesia syringae)
    Larvae are creamy white grubs with small dark heads and small prolegs on the abdomen with hook-like crochets at the tip.
  • Emerald ash borer (Agrilus planipennis)
    Larvae are 26-32 mm long, creamy white with triangular segments and a brownish head. Adults are 13 mm long with a metallic green color.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Mountain-ash sawfly (Pristophora geniculata)
    Adult sawflies are 9 mm long, black and look similar to wasps. Larvae are up to 20 mm long with pale green to yellow bodies with black spots and a blue or orange head.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Scab (Venturia inaequalis)
    Scab lesions (diseased areas) are often first noticed on leaves, where they most commonly occur on the upper leaf surface. Fruits are also very susceptible to infection. Lesions on both leaves and fruits are roughly circular with feathery edges, and have an olive green to black color. They can be as small as the size of a pinhead or as large a 1/2 inch in diameter. When the disease is severe, lesions can merge and cover a large portion of the leaf or fruit surface. Defoliation of the tree often follows.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Birch (Betula)

  • Animal damage ()
    Animals that do the most damage to herbaceous plants include: deer, rabbits and woodchucks. Deer damage is distinctive because deer only have teeth on their lower jaws, so when they bite down, they must tear the plant to pull off leaves. Thus, deer damage to plants is rough or shredded-looking. It may also be several feet off of the ground. Plus, if a large amount of plant material is damaged overnight, you should suspect deer. Rabbit damage looks like someone used a pruner to cut the plant off at a clean, 45-degree angle. Woodchucks will mow down plants, or sometimes just nibble on succulent material. They are diurnal, so keep on the lookout.
  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • Birch leaf skeletonizer (Bucculatrix canadensisella)
    Larvae are pale yellow, sometimes tinted with green and approximately 7mm long. White webs or cocoons may also be present on the undersides of leaves.
  • Birch leafminer (Fenusa pusilla)
    Larvae of these leafmining sawflies are yellowish-white, somewhat flat and can be up to 1/4" long. Find the larvae and dark frass in mined leaves. Adults are 1/4" long, black, thick-waisted wasps. Adults appear in early spring and lay eggs in the leaves. Larvae hatch soon after, feed for 2-3 weeks and drop to the ground to pupate. There are usually two generations per year.
  • Bronze birch borer (Agrilus anxius)
    Adults are flattened with antennae 1/4th their body length. Borers are 6-11 mm in length and olive black in color with coppery reflections. Larvae are 25 mm long, flat headed.
  • Cankerworms (Alsophila pometaria)
    Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner and are considered "inchworms". Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Eastern tent caterpillar (Malacosoma americanum)
    Larvae grow to greater than 25 mm in length. Caterpillars have black heads with a white stripe down the length of the back and a yellow stripe on each side with blue markings.
  • Elm sawfly (Cimbex americana)
    Larvae are pale yellow to green in color with a dark stripe down the back, which develops a pebbly skin when full grown.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Forest tent caterpillar (Malacosoma disstria)
    Larvae are 1.5-2" long, slightly fuzzy and gray with black spots and whitish 'keyhole' spots down the center of their backs. Flanking the spots on either side are longitudinal stripes in yellow and bright blue. Caterpillars live in large colonies and don't make 'tents', but rather rest on silken mats they've spun on larger branches and tree trunks. Scout for white cocoons within leaves or attached to fences or ground objects in June or July. Adults emerge 10-14 days later to lay about 200 whitish eggs in bands around twigs for overwintering purposes. Larvae hatch at about bud break in early spring. There is only 1 brood per year.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gypsy moth (Lymantria dispar)
    Larvae hatch at 3 mm long and black in color. Larvae will grow up to 50 mm in length with 5 pairs of blue spots toward the front and 6 pairs of red spots toward the rear of the caterpillar. Adults are moths.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Manganese deficiency - woody plants ()
    Manganese (Mn) deficiency is most likely to occur in neutral to high pH soils that are also high in organic matter. This is common in the red soils of eastern Wisconsin, especially in low-lying, poorly drained areas, and on burned-over organic soils. Symptoms of Mn deficiency in broadleaf trees/shrubs manifest as interveinal chlorosis sometimes worsening to necrosis, undersized leaves, or leaves with curly, wavy or crinkled leaf margins. Symptoms appear on new growth first. Acer rubrum is particularly susceptible to this condition. In conifers, Mn deficiency symptoms closely resemble those of iron (Fe) deficiency: chlorotic and stunted new growth, with the older growth remaining green. Symptoms are more likely to appear on drought-stressed or acid-loving plants.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Potato leafhopper (Empoasca fabae)
    Potato leafhoppers are small (1∕8" long), bright green, wedge-shaped insects with whitish spots on their head and thorax. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings and are smaller. There are typically 2 generations per year in WI; populations decline significantly in August. Insects do not overwinter here, but are blown in by southerly winds each spring.
  • Powdery mildew (woody plants) (Several)
    The upper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has h pper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has sprinkled them with talcum powder or powdered sugar.
  • Redhumped oakworm (Symmerista canicosta)
    Larvae are yellow with black and white longitudinal stripes, shiny red-orange heads and shiny red humps close to their posterier ends. They can reach 1-3/4" long. Adults are dark-brown to gray moths that appear from May to July, laying light green eggs in groups on the undersides of leaves. Larvae are light green at first and feed in groups. As they mature, they scatter. Pupae overwinter in ground litter in white cocoons. There is 1 generation per year.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Scorch ()
    The primary symptom of scorch is the browning of leaf edges or needles. Sometimes there will be a distinct yellow band between the leaf edges and the green inner leaf. On conifers, especially spruce, affected needles will turn reddish-purple then brown. Scorch itself is a symptom and not the root cause of the problem. Woody species often affected by scorch include: Acer, Abies, Fraxinus, Pinus, Quercus and Tilia. Scorch may not affect the whole plant uniformly. It is not generally fatal. However, if extensive damage is present by mid-summer, the plant's ability to make food will be reduced and it may be more susceptible to winter damage. Scorch usually results from the following: insufficient water (due to drought, improper siting, impaired root systems); a response to an undesirable soil or air constituent (salt accumulation or atmospheric chemicals); or a response to fungal or bacteria pathogens.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • White-marked tussock moth (Orygia leucostigma)
    Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.
  • Yellow-necked caterpillar (Datana ministra)
    Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.

Buckeye (Aesculus)

  • Animal damage ()
    Animals that do the most damage to herbaceous plants include: deer, rabbits and woodchucks. Deer damage is distinctive because deer only have teeth on their lower jaws, so when they bite down, they must tear the plant to pull off leaves. Thus, deer damage to plants is rough or shredded-looking. It may also be several feet off of the ground. Plus, if a large amount of plant material is damaged overnight, you should suspect deer. Rabbit damage looks like someone used a pruner to cut the plant off at a clean, 45-degree angle. Woodchucks will mow down plants, or sometimes just nibble on succulent material. They are diurnal, so keep on the lookout.
  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Manganese deficiency - woody plants ()
    Manganese (Mn) deficiency is most likely to occur in neutral to high pH soils that are also high in organic matter. This is common in the red soils of eastern Wisconsin, especially in low-lying, poorly drained areas, and on burned-over organic soils. Symptoms of Mn deficiency in broadleaf trees/shrubs manifest as interveinal chlorosis sometimes worsening to necrosis, undersized leaves, or leaves with curly, wavy or crinkled leaf margins. Symptoms appear on new growth first. Acer rubrum is particularly susceptible to this condition. In conifers, Mn deficiency symptoms closely resemble those of iron (Fe) deficiency: chlorotic and stunted new growth, with the older growth remaining green. Symptoms are more likely to appear on drought-stressed or acid-loving plants.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (Fusarium species (W))
    Symptoms include stunting, chlorosis, root necrosis and death of woody plants. Symptoms are dependent on cultural practices and the local environment.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Pythium species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Rhizoctonia species (W))
    Symptoms on the above ground parts of larger plants include necrotic spots and blotches on the leaves, shoot blight and dieback.
  • Root rot (woody plants) (Thielaviopsis species (W))
    Uncommonly damages woody plants in the landscape. Symptoms include stunting, sparse foliage, poor foliar color and die back after the death of fibrous roots
  • Scorch ()
    The primary symptom of scorch is the browning of leaf edges or needles. Sometimes there will be a distinct yellow band between the leaf edges and the green inner leaf. On conifers, especially spruce, affected needles will turn reddish-purple then brown. Scorch itself is a symptom and not the root cause of the problem. Woody species often affected by scorch include: Acer, Abies, Fraxinus, Pinus, Quercus and Tilia. Scorch may not affect the whole plant uniformly. It is not generally fatal. However, if extensive damage is present by mid-summer, the plant's ability to make food will be reduced and it may be more susceptible to winter damage. Scorch usually results from the following: insufficient water (due to drought, improper siting, impaired root systems); a response to an undesirable soil or air constituent (salt accumulation or atmospheric chemicals); or a response to fungal or bacteria pathogens.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
  • White-marked tussock moth (Orygia leucostigma)
    Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Catalpa (Catalpa)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Powdery mildew (woody plants) (Several)
    The upper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has h pper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has sprinkled them with talcum powder or powdered sugar.
  • Root rot (woody plants) (Thielaviopsis species (W))
    Uncommonly damages woody plants in the landscape. Symptoms include stunting, sparse foliage, poor foliar color and die back after the death of fibrous roots
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Southern blight (Sclerotium rolfsii)
    This disease is only active during hot weather. Plants may grow well in infested soil during most of the growing season and only be damaged during the hottest part of summer. Initial symptoms are yellowing or wilting of lower leaves, then basal stems decay, followed by the collapse of individual stems or entire plants. Inspection of the stem at the soil line reveals white mycelium (fungal strands) and small, tan spherical sclerotia (fungal survival structures) that resemble mustard seeds. Roots are unaffected. Decay of the stem at the soil line is common during hot, humid weather.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Coffeetree (Gymnocladus)

  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Crabapple (Malus)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Cankerworms (Alsophila pometaria)
    Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner and are considered "inchworms". Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs.
  • Cedar-rosaceous rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
    On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance.
  • Eastern tent caterpillar (Malacosoma americanum)
    Larvae grow to greater than 25 mm in length. Caterpillars have black heads with a white stripe down the length of the back and a yellow stripe on each side with blue markings.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Fire blight (Erwinia amylovora)
    Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Scab (Venturia inaequalis)
    Scab lesions (diseased areas) are often first noticed on leaves, where they most commonly occur on the upper leaf surface. Fruits are also very susceptible to infection. Lesions on both leaves and fruits are roughly circular with feathery edges, and have an olive green to black color. They can be as small as the size of a pinhead or as large a 1/2 inch in diameter. When the disease is severe, lesions can merge and cover a large portion of the leaf or fruit surface. Defoliation of the tree often follows.
  • Shothole borer (Scolytus rugulosus)
    Borers are small 1/10th inch gray-black beetles.
  • White-marked tussock moth (Orygia leucostigma)
    Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.
  • Woolly adelgids (Several)
    A family of woolly aphids that are associated with conifers. These are not true aphids but similar to woolly aphids in that their bodies are covered in white, cottony, wax-like threads that cause them to appear wooly.
  • Woolly aphids (Several)
    Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.
  • Yellow-necked caterpillar (Datana ministra)
    Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.

Elm (Ulmus)

  • Cankerworms (Alsophila pometaria)
    Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner and are considered "inchworms". Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs.
  • Dutch elm disease (Ophiostoma novo-ulmi)
    Wilting leaves, often on a single branch, are the first symptoms of Dutch elm disease. Yellowing of leaves and leaf drop follow. Trees may quickly lose all of their leaves, or trees may survive several years with an infection localized in a single branch. Infected branches often have brown streaks under the bark that follow the wood grain.
  • Elm leaf beetle (Pyrrhalta luteola)
    Adult beetles are 5-7 mm long and yellow to dullish green with a black stripe at the edge of each wing cover. There are three dark spots behind the head. Larvae are up to 12 mm in length, yellowish in color with two lines of black dots along the back.
  • Elm leafminer (Kaliofenusa ulmi)
    Mature larvae are 45 mm long, wrinkled and yellowish to greenish white with a median black stripe and many whitish stripes that makes its skin appear grainy.
  • Elm sawfly (Cimbex americana)
    Larvae are pale yellow to green in color with a dark stripe down the back, which develops a pebbly skin when full grown.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Spiny elm caterpillar (Nymphalis antiopa)
    Dark colored caterpillar with purple markings. Adult is the Morning Cloak Butterfly.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
  • Yellow-necked caterpillar (Datana ministra)
    Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.

Filbert (Corylus)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Powdery mildew (woody plants) (Several)
    The upper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has h pper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has sprinkled them with talcum powder or powdered sugar.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Hackberry (Celtis)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • Cankerworms (Alsophila pometaria)
    Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner and are considered "inchworms". Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Downy mildew (Woody plants) (Peronosporaceae family)
  • Eriophyid mite (Eriophyes species)
    Adults are elongated and have two sets of anterior legs. Most species are less than 1 mm long and difficult to identify without a microscope. Color is variable but most are white to yellow.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Hackberry nipple gall (Pachypsylla celtidismamma)
    Adults are psylliads that resemble miniature cicadas. Mottled light brown in color, 4-5 mm long with wings that peak over the back.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Manganese deficiency - woody plants ()
    Manganese (Mn) deficiency is most likely to occur in neutral to high pH soils that are also high in organic matter. This is common in the red soils of eastern Wisconsin, especially in low-lying, poorly drained areas, and on burned-over organic soils. Symptoms of Mn deficiency in broadleaf trees/shrubs manifest as interveinal chlorosis sometimes worsening to necrosis, undersized leaves, or leaves with curly, wavy or crinkled leaf margins. Symptoms appear on new growth first. Acer rubrum is particularly susceptible to this condition. In conifers, Mn deficiency symptoms closely resemble those of iron (Fe) deficiency: chlorotic and stunted new growth, with the older growth remaining green. Symptoms are more likely to appear on drought-stressed or acid-loving plants.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Potato leafhopper (Empoasca fabae)
    Potato leafhoppers are small (1∕8" long), bright green, wedge-shaped insects with whitish spots on their head and thorax. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings and are smaller. There are typically 2 generations per year in WI; populations decline significantly in August. Insects do not overwinter here, but are blown in by southerly winds each spring.
  • Powdery mildew (woody plants) (Several)
    The upper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has h pper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has sprinkled them with talcum powder or powdered sugar.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.
  • Woolly aphids (Several)
    Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.

Hawthorn (Crataegus)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • Cankerworms (Alsophila pometaria)
    Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner and are considered "inchworms". Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs.
  • Cedar-rosaceous rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
    On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cottony maple scale (Pulvinaria innumerabilis)
    Flat and pale brown to dark brown, Scales form protruding white egg sacs which are over 1/4th of an inch when the egg mass swells.
  • Cucumber beetle (Spotted/Striped) (Chrysomelidae family (CB))
    Larvae are pale-colored and wormlike with brown heads. Adult spotted cucumber beetles are about 1/4" long, with shiny black heads and greenish-yellow with 12 black spots on their backs. Adult striped cucumber beetles are about 1/4" long, with shiny black heads and are yellowish-orange with 3 black stripes. There may be 1-2 generations of each type of cucumber beetle per year.
  • Cytospora canker (Cytospora species)
    A stem and branch disorder affecting many different types of conifers. In Wisconsin, Colorado Blue Spruce is the main species that is affected.
  • Eastern tent caterpillar (Malacosoma americanum)
    Larvae grow to greater than 25 mm in length. Caterpillars have black heads with a white stripe down the length of the back and a yellow stripe on each side with blue markings.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Fire blight (Erwinia amylovora)
    Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown.
  • Forest tent caterpillar (Malacosoma disstria)
    Larvae are 1.5-2" long, slightly fuzzy and gray with black spots and whitish 'keyhole' spots down the center of their backs. Flanking the spots on either side are longitudinal stripes in yellow and bright blue. Caterpillars live in large colonies and don't make 'tents', but rather rest on silken mats they've spun on larger branches and tree trunks. Scout for white cocoons within leaves or attached to fences or ground objects in June or July. Adults emerge 10-14 days later to lay about 200 whitish eggs in bands around twigs for overwintering purposes. Larvae hatch at about bud break in early spring. There is only 1 brood per year.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Gypsy moth (Lymantria dispar)
    Larvae hatch at 3 mm long and black in color. Larvae will grow up to 50 mm in length with 5 pairs of blue spots toward the front and 6 pairs of red spots toward the rear of the caterpillar. Adults are moths.
  • Hawthorn leafminer (Profenusa canadensis)
    Adults emerge in early May and begin laying eggs within leaves. Larvae hatch soon after and start mining. Larvae usually drop to the ground to pupate by the end of May. Insects overwinter in soil. There is 1 generation per year.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Leafhoppers (Several)
    3-15 mm in length, wedge shaped with wings that peak over their backs. Nymphs are wingless but active and move readily when disturbed. Adults are winged and fly readily when disturbed.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Pearslug sawfly (Caliroa cerasi)
    Adults are small, stout, shiny black wasps about 1/3" long that emerge in late June or early July. Eggs are inserted one by one in circular slits on the upper surfaces of leaves and hatch about 2 weeks later. Larvae are shiny, slimy, swollen at the head end, and range in color from olive green to orangeish-green. Full grown larvae leave plants to pupate in the soil and may emerge as adults in about 2 more weeks to produce a 2nd generation. Some remain dormant until the following spring.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Powdery mildew (woody plants) (Several)
    The upper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has h pper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has sprinkled them with talcum powder or powdered sugar.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Shothole borer (Scolytus rugulosus)
    Borers are small 1/10th inch gray-black beetles.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Southern blight (Sclerotium rolfsii)
    This disease is only active during hot weather. Plants may grow well in infested soil during most of the growing season and only be damaged during the hottest part of summer. Initial symptoms are yellowing or wilting of lower leaves, then basal stems decay, followed by the collapse of individual stems or entire plants. Inspection of the stem at the soil line reveals white mycelium (fungal strands) and small, tan spherical sclerotia (fungal survival structures) that resemble mustard seeds. Roots are unaffected. Decay of the stem at the soil line is common during hot, humid weather.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • Walnut caterpillar (Datana integerrina)
    Larvae are 50 mm long when mature and gray to black with long hairs. Younger larvae are reddish brown with light yellow stripes down the length of their bodies. Adults are stout bodied moths.
  • Woolly aphids (Several)
    Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.
  • Yellow-necked caterpillar (Datana ministra)
    Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.

Hickory (Carya)

  • Animal damage ()
    Animals that do the most damage to herbaceous plants include: deer, rabbits and woodchucks. Deer damage is distinctive because deer only have teeth on their lower jaws, so when they bite down, they must tear the plant to pull off leaves. Thus, deer damage to plants is rough or shredded-looking. It may also be several feet off of the ground. Plus, if a large amount of plant material is damaged overnight, you should suspect deer. Rabbit damage looks like someone used a pruner to cut the plant off at a clean, 45-degree angle. Woodchucks will mow down plants, or sometimes just nibble on succulent material. They are diurnal, so keep on the lookout.
  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • Cankerworms (Alsophila pometaria)
    Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner and are considered "inchworms". Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gypsy moth (Lymantria dispar)
    Larvae hatch at 3 mm long and black in color. Larvae will grow up to 50 mm in length with 5 pairs of blue spots toward the front and 6 pairs of red spots toward the rear of the caterpillar. Adults are moths.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Hickory leaf stem gall phylloxera (Phylloxera caryaecaulis)
    Closely related to aphids. Species is usually identified by gall formation.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Manganese deficiency - woody plants ()
    Manganese (Mn) deficiency is most likely to occur in neutral to high pH soils that are also high in organic matter. This is common in the red soils of eastern Wisconsin, especially in low-lying, poorly drained areas, and on burned-over organic soils. Symptoms of Mn deficiency in broadleaf trees/shrubs manifest as interveinal chlorosis sometimes worsening to necrosis, undersized leaves, or leaves with curly, wavy or crinkled leaf margins. Symptoms appear on new growth first. Acer rubrum is particularly susceptible to this condition. In conifers, Mn deficiency symptoms closely resemble those of iron (Fe) deficiency: chlorotic and stunted new growth, with the older growth remaining green. Symptoms are more likely to appear on drought-stressed or acid-loving plants.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Powdery mildew (woody plants) (Several)
    The upper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has h pper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has sprinkled them with talcum powder or powdered sugar.
  • Redhumped oakworm (Symmerista canicosta)
    Larvae are yellow with black and white longitudinal stripes, shiny red-orange heads and shiny red humps close to their posterier ends. They can reach 1-3/4" long. Adults are dark-brown to gray moths that appear from May to July, laying light green eggs in groups on the undersides of leaves. Larvae are light green at first and feed in groups. As they mature, they scatter. Pupae overwinter in ground litter in white cocoons. There is 1 generation per year.
  • Root rot (woody plants) (Cylindrocladium species)
    Root infections are characterized by many dark brown to black lesions often with longitudinal cracks. Severe root disease leads to stunting, wilting, yellowing and death. Stem infections of both conifers and broadleaves arise at the leaf bases and may girdle small stems. Diseased conifer needles turn yellow or red-brown. Dark lesions form in the leaves of broadleaf plants. Leaf blight leads to defoliation.
  • Scorch ()
    The primary symptom of scorch is the browning of leaf edges or needles. Sometimes there will be a distinct yellow band between the leaf edges and the green inner leaf. On conifers, especially spruce, affected needles will turn reddish-purple then brown. Scorch itself is a symptom and not the root cause of the problem. Woody species often affected by scorch include: Acer, Abies, Fraxinus, Pinus, Quercus and Tilia. Scorch may not affect the whole plant uniformly. It is not generally fatal. However, if extensive damage is present by mid-summer, the plant's ability to make food will be reduced and it may be more susceptible to winter damage. Scorch usually results from the following: insufficient water (due to drought, improper siting, impaired root systems); a response to an undesirable soil or air constituent (salt accumulation or atmospheric chemicals); or a response to fungal or bacteria pathogens.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Walnut caterpillar (Datana integerrina)
    Larvae are 50 mm long when mature and gray to black with long hairs. Younger larvae are reddish brown with light yellow stripes down the length of their bodies. Adults are stout bodied moths.
  • Yellow-necked caterpillar (Datana ministra)
    Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.

Honeylocust (Gleditsia )

  • Honey locust plantbug (Diaphnocoris chlorionis)
    Adults are winged pale green and 5-6 mm in length. Nymphs are a smaller version of the adults with short wing buds.
  • Honey locust podgall midge (Dasineura gleditschiae)
    Adults are tiny midges generally black with a reddish abdomen. Larvae are cream colored maggots found in the pod galls.
  • Honey locust spider mite (Platytetranychus multidigituli)
    Tiny (1 mm) orange mite, turning pale yellow to green as they mature.
  • Leafhoppers (Several)
    3-15 mm in length, wedge shaped with wings that peak over their backs. Nymphs are wingless but active and move readily when disturbed. Adults are winged and fly readily when disturbed.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.

Linden (Tilia)

  • Cankerworms (Alsophila pometaria)
    Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner and are considered "inchworms". Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Linden borer (Saperda vestia)
    Primary color is olive green to yellow brown because of hairs covering the dark colored body. Most have dark spots on each wing cover, two above the middle of the wing and one below.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • White-marked tussock moth (Orygia leucostigma)
    Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.

Locust (Robinia)

  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Magnolia (Magnolia)

  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Maple (Acer)

  • Animal damage ()
    Animals that do the most damage to herbaceous plants include: deer, rabbits and woodchucks. Deer damage is distinctive because deer only have teeth on their lower jaws, so when they bite down, they must tear the plant to pull off leaves. Thus, deer damage to plants is rough or shredded-looking. It may also be several feet off of the ground. Plus, if a large amount of plant material is damaged overnight, you should suspect deer. Rabbit damage looks like someone used a pruner to cut the plant off at a clean, 45-degree angle. Woodchucks will mow down plants, or sometimes just nibble on succulent material. They are diurnal, so keep on the lookout.
  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Cankerworms (Alsophila pometaria)
    Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner and are considered "inchworms". Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cottony maple scale (Pulvinaria innumerabilis)
    Flat and pale brown to dark brown, Scales form protruding white egg sacs which are over 1/4th of an inch when the egg mass swells.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Eastern tent caterpillar (Malacosoma americanum)
    Larvae grow to greater than 25 mm in length. Caterpillars have black heads with a white stripe down the length of the back and a yellow stripe on each side with blue markings.
  • Elm sawfly (Cimbex americana)
    Larvae are pale yellow to green in color with a dark stripe down the back, which develops a pebbly skin when full grown.
  • Eriophyid mite (Eriophyes species)
    Adults are elongated and have two sets of anterior legs. Most species are less than 1 mm long and difficult to identify without a microscope. Color is variable but most are white to yellow.
  • Flea beetle (Chrysomelidae family)
    Flea beetles are among the smallest of the leaf beetles, typically smaller than 1/6" long. They usually possess large rear legs used for jumping. Several species are found in Wisconsin.
  • Forest tent caterpillar (Malacosoma disstria)
    Larvae are 1.5-2" long, slightly fuzzy and gray with black spots and whitish 'keyhole' spots down the center of their backs. Flanking the spots on either side are longitudinal stripes in yellow and bright blue. Caterpillars live in large colonies and don't make 'tents', but rather rest on silken mats they've spun on larger branches and tree trunks. Scout for white cocoons within leaves or attached to fences or ground objects in June or July. Adults emerge 10-14 days later to lay about 200 whitish eggs in bands around twigs for overwintering purposes. Larvae hatch at about bud break in early spring. There is only 1 brood per year.
  • Four-lined plant bug (Poecilocapsus lineatus)
    Adults are 1/4-1/3" long, and yellow to yellow-green with four longitudinal black lines down the wing covers, and black antennae. Nymphs are bright red-orange with black dots on the abdomen. Insect has a short lifecyle beginning in late April/early May. Adult activity outdoors is over by the end of spring. One generation produced annually.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gypsy moth (Lymantria dispar)
    Larvae hatch at 3 mm long and black in color. Larvae will grow up to 50 mm in length with 5 pairs of blue spots toward the front and 6 pairs of red spots toward the rear of the caterpillar. Adults are moths.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Leafhoppers (Several)
    3-15 mm in length, wedge shaped with wings that peak over their backs. Nymphs are wingless but active and move readily when disturbed. Adults are winged and fly readily when disturbed.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Manganese deficiency - woody plants ()
    Manganese (Mn) deficiency is most likely to occur in neutral to high pH soils that are also high in organic matter. This is common in the red soils of eastern Wisconsin, especially in low-lying, poorly drained areas, and on burned-over organic soils. Symptoms of Mn deficiency in broadleaf trees/shrubs manifest as interveinal chlorosis sometimes worsening to necrosis, undersized leaves, or leaves with curly, wavy or crinkled leaf margins. Symptoms appear on new growth first. Acer rubrum is particularly susceptible to this condition. In conifers, Mn deficiency symptoms closely resemble those of iron (Fe) deficiency: chlorotic and stunted new growth, with the older growth remaining green. Symptoms are more likely to appear on drought-stressed or acid-loving plants.
  • Maple gall mite (bladder and spindle) (Vasates species)
    Adult eeriophid mites are not visible without the aid of a dissecting scope. Mites are 0.05 - 0.2 mm in length and spindle shaped with 4 anterior legs.
  • Maple petiole borer (Caulocampus acericaulis)
    Adults are stem-boring sawflies that lay eggs in late April and May. Larvae burrow into leaf petioles, causing them to break near the leaf blades. Larvae pupate in the soil. There is 1 generation per year.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Potato leafhopper (Empoasca fabae)
    Potato leafhoppers are small (1∕8" long), bright green, wedge-shaped insects with whitish spots on their head and thorax. Both adults and nymphs are strong hoppers. Adults hold their wings rooflike over their abdomens. Nymphs resemble adults except they lack wings and are smaller. There are typically 2 generations per year in WI; populations decline significantly in August. Insects do not overwinter here, but are blown in by southerly winds each spring.
  • Redhumped oakworm (Symmerista canicosta)
    Larvae are yellow with black and white longitudinal stripes, shiny red-orange heads and shiny red humps close to their posterier ends. They can reach 1-3/4" long. Adults are dark-brown to gray moths that appear from May to July, laying light green eggs in groups on the undersides of leaves. Larvae are light green at first and feed in groups. As they mature, they scatter. Pupae overwinter in ground litter in white cocoons. There is 1 generation per year.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Pythium species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Rhizoctonia species (W))
    Symptoms on the above ground parts of larger plants include necrotic spots and blotches on the leaves, shoot blight and dieback.
  • Root rot (woody plants) (Thielaviopsis species (W))
    Uncommonly damages woody plants in the landscape. Symptoms include stunting, sparse foliage, poor foliar color and die back after the death of fibrous roots
  • Scorch ()
    The primary symptom of scorch is the browning of leaf edges or needles. Sometimes there will be a distinct yellow band between the leaf edges and the green inner leaf. On conifers, especially spruce, affected needles will turn reddish-purple then brown. Scorch itself is a symptom and not the root cause of the problem. Woody species often affected by scorch include: Acer, Abies, Fraxinus, Pinus, Quercus and Tilia. Scorch may not affect the whole plant uniformly. It is not generally fatal. However, if extensive damage is present by mid-summer, the plant's ability to make food will be reduced and it may be more susceptible to winter damage. Scorch usually results from the following: insufficient water (due to drought, improper siting, impaired root systems); a response to an undesirable soil or air constituent (salt accumulation or atmospheric chemicals); or a response to fungal or bacteria pathogens.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Taxus mealybug (Phenacoccus acericola)
    A small soft bodied insect covered with fine whitish wax, similar in appearance to soft scale.
  • Thrips (Order Thysanoptera)
    Minute insects usually identifiable only under high-powered magnification. Thrips have a modified, single mandible that they use to puncture plant tissue. They then feed on the sap that exudes from the resulting wound. Larvae drop to the soil to pupate. Adult insects like flowers with an open structures where the stamen and pistil are readily available.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
  • White-marked tussock moth (Orygia leucostigma)
    Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.
  • Woolly aphids (Several)
    Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.
  • Yellow-necked caterpillar (Datana ministra)
    Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.

Mountain Ash (Sorbus)

  • Cedar-rosaceous rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
    On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.

Oak (Quercus)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Cankerworms (Alsophila pometaria)
    Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner and are considered "inchworms". Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Oak leaf gall (Several)
    Several different wasp species cause galls on oak leaves.
  • Oak leaf skeletonizer (Bucculatrix ainsliella)
    Larvae are pale yellow, sometimes tinted with green and approximately 7mm long. If larvae are disturbed they may spin long silken threads and hang from branches. White webs or cocoons may also be present.
  • Oak leafminer (Cameraria species)
    Several species cause mines in oak leaves.
  • Oak wilt (Ceratocystis fagacearum)
    Initially, single branches on infected trees wilt and die. Leaves on these branches often bronze, or turn tan or dull green, starting at the tips or outer margins. Leaves may also droop, curl, or fall from the tree. Infected trees eventually die. Oak wilt can kill oaks in the red oak group in less than one month. Oaks in the white oak group usually have less severe symptoms and are rarely killed in one season.
  • Twolined chestnut borer (Agrilus bilineatus)
    Borers are 6-12 mm long, greenish black, with fine golden yellow hairs and a pale stripe on each wing cover. Larvae are up to 25 mm long, slender, legless and cream in color.
  • Yellow-necked caterpillar (Datana ministra)
    Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.

Pear (Pyrus)

  • Fire blight (Erwinia amylovora)
    Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown.

Plum / Cherry (Prunus)

  • Bacterial leaf spot & twig blight (Pseudomonas syringae pv. Syringae)
    Initial symptoms of bacterial blight may include dark brown necrotic (dead) leaf spots with yellow margins. If leaf spots develop before leaves are fully expanded, leaf curling and twisting may result. More advanced symptoms include necrotic blotches starting at the leaf margins and advancing inward, as well as black streaking on twigs. In its' most severe form, bacterial blight can result in the death of branch tips, leaves and blossoms.
  • Black knot (Apiosporina morbosa)
    During the first year of infection, black knot-infected trees develop greenish-brown to brown swellings on affected branches and trunks. During the second year, these swellings enlarge into the ugly, black, erupting tumors (galls) characteristic of the disease. Older gall tissue (greater than two years old) often dies and then is colonized by fungi that give the gall a whitish or pinkish color. Severe black knot infections may cause general tree decline or death if galls girdle large limbs or tree trunks.
  • Cankerworms (Alsophila pometaria)
    Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner and are considered "inchworms". Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs.
  • Eastern tent caterpillar (Malacosoma americanum)
    Larvae grow to greater than 25 mm in length. Caterpillars have black heads with a white stripe down the length of the back and a yellow stripe on each side with blue markings.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Peachtree borer (Synanthedon exitiosa)
    Larvae are creamy white with a reddish brown head.
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
  • Yellow-necked caterpillar (Datana ministra)
    Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.

Poplar (Populus)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.

Redbud (Cercis)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Downy mildew (Woody plants) (Peronosporaceae family)
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Leafhoppers (Several)
    3-15 mm in length, wedge shaped with wings that peak over their backs. Nymphs are wingless but active and move readily when disturbed. Adults are winged and fly readily when disturbed.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (woody plants) (Cylindrocladium species)
    Root infections are characterized by many dark brown to black lesions often with longitudinal cracks. Severe root disease leads to stunting, wilting, yellowing and death. Stem infections of both conifers and broadleaves arise at the leaf bases and may girdle small stems. Diseased conifer needles turn yellow or red-brown. Dark lesions form in the leaves of broadleaf plants. Leaf blight leads to defoliation.
  • Scorch ()
    The primary symptom of scorch is the browning of leaf edges or needles. Sometimes there will be a distinct yellow band between the leaf edges and the green inner leaf. On conifers, especially spruce, affected needles will turn reddish-purple then brown. Scorch itself is a symptom and not the root cause of the problem. Woody species often affected by scorch include: Acer, Abies, Fraxinus, Pinus, Quercus and Tilia. Scorch may not affect the whole plant uniformly. It is not generally fatal. However, if extensive damage is present by mid-summer, the plant's ability to make food will be reduced and it may be more susceptible to winter damage. Scorch usually results from the following: insufficient water (due to drought, improper siting, impaired root systems); a response to an undesirable soil or air constituent (salt accumulation or atmospheric chemicals); or a response to fungal or bacteria pathogens.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
  • White-marked tussock moth (Orygia leucostigma)
    Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.

Russian Olive (Elaeagnus )

  • Phomopsis canker (Phomopsis species)
    Kills seedlings/saplings and causes cankers on larger plants. Shriveled, faded foliage can be found on dead branches and small trees from midsummer to fall. Young cankers in smooth-barked branches are reddish-brown to black. An amber-brown gum is often exuded from lesions. Cankers on trunks and scaffold limbs appear as dark, depressed areas leading to splits in the bark. Within a month after infection, pimply eruptions appear on the surface. Initially grayish-tan, eruptions darken with age and eventually turn black. Usually they are abundant by the time the disease is detected but remain prominent for at least a year.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Serviceberry (Amelanchier)

  • Animal damage ()
    Animals that do the most damage to herbaceous plants include: deer, rabbits and woodchucks. Deer damage is distinctive because deer only have teeth on their lower jaws, so when they bite down, they must tear the plant to pull off leaves. Thus, deer damage to plants is rough or shredded-looking. It may also be several feet off of the ground. Plus, if a large amount of plant material is damaged overnight, you should suspect deer. Rabbit damage looks like someone used a pruner to cut the plant off at a clean, 45-degree angle. Woodchucks will mow down plants, or sometimes just nibble on succulent material. They are diurnal, so keep on the lookout.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Cedar-rosaceous rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
    On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance.
  • Chlorosis (Woody plants) ()
    Affected leaves turn yellow, except the veins, which remain green. In severe cases, foliage may turn brown and die. Affected foliage can occur on isolated branches, or over the entire tree or shrub. The cause of chlorosis is the lack of certain micronutrients, in many cases iron. This may be due to poor fertilization or to the plant's inability to uptake the nutrients from the soil by the roots. Poor absorption of micronutrients is common in Wisconsin because of the high pH (alkalinity) of many of our soils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gas Injury ()
    Symptoms of gas injury can range from slow growth to total plant death, and initially resemble symptoms of water stress. Gas injury may also be mistaken for compacted soil, root disease, herbicide injury or air pollution. Symptoms include: slow growth, small leaves, wilt and leaf drop. Roots may be bluish and water-soaked, and surrounding soils may turn bluish gray or black. The injury may progress over time. Gas injury may occur from gas released into the soil or into the air. Root zone injury from gas leaks in soil usually stems from gas or sewer-line breaks (rapid damage) or gases leaking from landfills (gradual damage). The extent of damage depends on the size of the leak, when it occurs (summer is worse), soil type (heavier is worse) and the amount of paving surrounding the plants. Gas injury due to atmospheric gas leaks usually stems from vents, chimneys, smokestacks or industrial equipment, and may or may not be phytotoxic. These releases are usually accidental and short-lived.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Gypsy moth (Lymantria dispar)
    Larvae hatch at 3 mm long and black in color. Larvae will grow up to 50 mm in length with 5 pairs of blue spots toward the front and 6 pairs of red spots toward the rear of the caterpillar. Adults are moths.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Japanese beetle (Popillia japonica)
    Adults are 12 mm long with a metallic green, oval body, dark green legs and copper colored wings with 5 hair like white tufts along the margin.
  • Lace bugs (Tingidae species)
    Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back.
  • Manganese deficiency - woody plants ()
    Manganese (Mn) deficiency is most likely to occur in neutral to high pH soils that are also high in organic matter. This is common in the red soils of eastern Wisconsin, especially in low-lying, poorly drained areas, and on burned-over organic soils. Symptoms of Mn deficiency in broadleaf trees/shrubs manifest as interveinal chlorosis sometimes worsening to necrosis, undersized leaves, or leaves with curly, wavy or crinkled leaf margins. Symptoms appear on new growth first. Acer rubrum is particularly susceptible to this condition. In conifers, Mn deficiency symptoms closely resemble those of iron (Fe) deficiency: chlorotic and stunted new growth, with the older growth remaining green. Symptoms are more likely to appear on drought-stressed or acid-loving plants.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nitrogen Overapplication ()
    Excessive nitrogen (N) application produces 'too rapid' growth which results in softness of tissue and general plant weakness. While N spurs green growth, flowers and seed formation will be greatly reduced. Plants with excess N are more susceptible to disease and injury.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Pearslug sawfly (Caliroa cerasi)
    Adults are small, stout, shiny black wasps about 1/3" long that emerge in late June or early July. Eggs are inserted one by one in circular slits on the upper surfaces of leaves and hatch about 2 weeks later. Larvae are shiny, slimy, swollen at the head end, and range in color from olive green to orangeish-green. Full grown larvae leave plants to pupate in the soil and may emerge as adults in about 2 more weeks to produce a 2nd generation. Some remain dormant until the following spring.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (Fusarium species (W))
    Symptoms include stunting, chlorosis, root necrosis and death of woody plants. Symptoms are dependent on cultural practices and the local environment.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Pythium species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Rhizoctonia species (W))
    Symptoms on the above ground parts of larger plants include necrotic spots and blotches on the leaves, shoot blight and dieback.
  • Root rot (woody plants) (Thielaviopsis species (W))
    Uncommonly damages woody plants in the landscape. Symptoms include stunting, sparse foliage, poor foliar color and die back after the death of fibrous roots
  • San Jose scale (Quadraspidiotus perniciosus)
    Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
  • Scorch ()
    The primary symptom of scorch is the browning of leaf edges or needles. Sometimes there will be a distinct yellow band between the leaf edges and the green inner leaf. On conifers, especially spruce, affected needles will turn reddish-purple then brown. Scorch itself is a symptom and not the root cause of the problem. Woody species often affected by scorch include: Acer, Abies, Fraxinus, Pinus, Quercus and Tilia. Scorch may not affect the whole plant uniformly. It is not generally fatal. However, if extensive damage is present by mid-summer, the plant's ability to make food will be reduced and it may be more susceptible to winter damage. Scorch usually results from the following: insufficient water (due to drought, improper siting, impaired root systems); a response to an undesirable soil or air constituent (salt accumulation or atmospheric chemicals); or a response to fungal or bacteria pathogens.
  • Shothole borer (Scolytus rugulosus)
    Borers are small 1/10th inch gray-black beetles.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Spider mites (Tetranychidae family)
    Family includes the majority of mites that cause plant damage. Larvae are smaller with 6 legs with adults being larger and having 8 legs. Spider mites vary in color and size by species with many being microscopic.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.
  • Woolly aphids (Several)
    Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.
  • Yellow-necked caterpillar (Datana ministra)
    Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.

Sycamore (Platanus)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.

Tuliptree (Liriodendron )

  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Walnut (Juglans)

  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Walnut caterpillar (Datana integerrina)
    Larvae are 50 mm long when mature and gray to black with long hairs. Younger larvae are reddish brown with light yellow stripes down the length of their bodies. Adults are stout bodied moths.
  • White-marked tussock moth (Orygia leucostigma)
    Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.
  • Yellow-necked caterpillar (Datana ministra)
    Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.

Willow (Salix)

  • Fall webworm (Hyphantria cunea)
    Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
  • Imported willow leaf beetle (Plagiodera versicolor)
    Larvae are up to 6 mm in length, black to dark bluish green with rows of tubercles along the body. Adults are 4-5 mm long, greenish blue and oval in shape.
  • Lecanium scale (Parthenolecanium species)
    Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Spiny elm caterpillar (Nymphalis antiopa)
    Dark colored caterpillar with purple markings. Adult is the Morning Cloak Butterfly.

Woody Ornamentals-Vines

Clematis (Clematis)

  • Animal damage ()
    Animals that do the most damage to herbaceous plants include: deer, rabbits and woodchucks. Deer damage is distinctive because deer only have teeth on their lower jaws, so when they bite down, they must tear the plant to pull off leaves. Thus, deer damage to plants is rough or shredded-looking. It may also be several feet off of the ground. Plus, if a large amount of plant material is damaged overnight, you should suspect deer. Rabbit damage looks like someone used a pruner to cut the plant off at a clean, 45-degree angle. Woodchucks will mow down plants, or sometimes just nibble on succulent material. They are diurnal, so keep on the lookout.
  • Anthracnose (Several)
    Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
  • Blister beetles (Meloidae family)
    Adults are about 1" long plus with soft, narrow, elongate bodies. Their wing-covers are rounded over the cylindrical body and their large heads are set off from the thorax. If handled, be warned that these beetles contain a defensive oil (cantharidin) which can cause skin to blister. There is one generation per year and adults are active from late May through September.
  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.
  • Cucumber mosaic (Cucumber mosaic virus)
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Viruses can retard plant growth and change the appearance of foliage, flowers and fruits. Virus-infected leaves can become spotted, streaked or mottled; they may be distorted or stunted. Veins may lose their color or develop outgrowths. Flowers can be dwarfed, deformed, streaked, faded, or they can remain green and develop into leaf-like structures.
  • Earwig (Forficula auricularia)
    Adults are about 1/2" long with prominent pincers on their hind ends, and reddish brown with lighter-colored, short wing covers on the thorax. Earwigs overwinter in the adult stage. Females lay eggs twice in a season, but there is only 1 generation per year. Foraging occurs at night, with movement to dark, sheltered areas during the day.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Inchworms (cankerworm, loopers, spanworms) (Geometridae family)
    Inchworms are a collective group of caterpillars including cankerworms, loopers and spanworms. These larvae move distinctively, contracting their bodies into a hump, then extending straight due to only 2-3 sets of prolegs. Colors vary widely depending on species. Female adults are usually wingless and lay egg masses on small twigs, under bark or in trunk crevices. Larvae descend from trees on silk strands when they're ready to pupate, landing on anything in their path.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Overwatering ()
    Overwatering, whether acute or chronic, is usually a death sentence for plants, especially when accompanied with poor drainage. Waterlogged soils limit oxygen uptake by plant roots, which in turn affects the plant's metabolism, nutrient uptake, water absorption and photosynthesis. Symptoms vary from slow growth to plant death and can include: leaf necrosis, dieback, root discoloration, soil blackening, foul odors, slow growth, thinning canopy and chlorosis. Overwatered conifer symptoms are similar, except they can also exhibit needle drop. Overwatering is common in irrigated landscapes, plantings at the bottoms of slopes and in poorly drained containers.
  • Oystershell scale (Lepidosaphes ulmi)
    Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
  • Powdery mildew (woody plants) (Several)
    The upper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has h pper and/or (less frequently) lower surface of leaves, as well as stems of infected plants, have a white, powdery appearance. They look as though someone has sprinkled them with talcum powder or powdered sugar.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Pythium species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Rhizoctonia species (W))
    Symptoms on the above ground parts of larger plants include necrotic spots and blotches on the leaves, shoot blight and dieback.
  • Root rot (woody plants) (Thielaviopsis species (W))
    Uncommonly damages woody plants in the landscape. Symptoms include stunting, sparse foliage, poor foliar color and die back after the death of fibrous roots
  • Slug (Order Sytlomatophora)
    Garden slugs are terrestrial mollusks, essentially snails without shells. As they move, they coat surfaces with a silvery, slimy substance. Most feed at night or during dark, cloudy days. Trails and feeding injuries are usually noticed before the slug itself. Slugs overwinter either as adults or as eggs. They become active during the first warm days of spring, and thrive under cool, damp conditions. Populations will be high during/following damp, rainy weather, and will almost disappear during dry periods. Slugs cannot survive direct sunlight. Rock walls, boards, pots and plant debris, as well as shaded flower beds and heavily mulched gardens, serve as ideal daytime resting sites.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Tarnished plant bug (Lygus lineolaris)
    Adults are 1/4" long, generally oval and about twice as long as wide. They are usually brownish with some yellow and reddish markings. Insect color tends to darken with age. Nymphs are more rounded, yellowish green to dark green, and often have dark spots. Adults overwinter in sheltered sites and become active in early spring. Several generations are produced annually.
  • Two-spotted spider mite (Tetranychus urticae)
    This most common spider mite is miniscule (0.5mm) and prefers to colonize and lay eggs on leaf undersides of most host plants. When populations are high, these mites can be found on all leaf surfaces and stems.
  • Whitefly (Aleyrodidae family)
    Adult whiteflies are small (1-2mm), white, fly-like insects related to scales, aphids and mealybugs. Their color comes from wax they create to cover their bodies. All whitefly stages are usually found on the undersides of leaves. There can be several generations per year depending on the environment.
  • Winter salt injury ()
    De-icing salts accumulate in the soil along streets/sidewalks or may be dispersed in an aerosol spray by fast-moving traffic and high winds along wet, salted roads. Salt spray can travel hundreds of feet from the roads where it originated. Symptoms can be similar to other abiotic plant problems, but there are tell-tale indicators including: Damage is more severe on sides of plants facing roads/sidewalks; severity of damage increases with volume/speed of traffic and amount of salt used; plants downwind from roads show more damage than those upwind; most damage occurs within 60' of road and decreases with distance; branches covered by snow or otherwise sheltered show no damage; branches growing above spray drift zone show no damage. Symptoms in deciduous plants include: delayed budbreak; reduced leaf size/stem growth; off-colored foliage; scorched leaves; no flowering; bud/twig death; and branch-tip dieback leading to 'witches' broom' growth below the dead area. Symptoms on conifers include: tips of mature needles turn brown or yellow, discoloration moves down needle eventually killing all of it, then needles fall off; twig dieback; and symptoms manifest only on sides of plants facing roads/sidewalks.

Pachysandra (Pachysandra)

  • Common aphids (Several)
    Numerous species with colors ranging from yellow to red to black with short oval bodies. Aphids are small but vary in size.

© 2014 Board of Regents of the University of Wisconsin System, doing business as the Division of Cooperative Extension of the University of Wisconsin-Extension. If you have any questions regarding this site's contents, trouble accessing any information on this site, require this information in an alternative format or would like to request a reasonable accommodation because of a disability email: greenindustry@ces.uwex.edu