Diagnostics

Herbaceous Ornamentals

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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.

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.
  • 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 (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.
  • 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.
  • 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.

Cyclamen (Cyclamen)

  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.

Herbaceous Ornamentals-Annuals

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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

Fountain plant, Love-lies-bleeding (Amaranth)

  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.

Columbine (Aquilegia)

  • 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.
  • 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.
  • 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.

Common or Rose Mallow (Althaea)

  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.

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.
  • 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.

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.

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 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.
  • 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.

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.
  • 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 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.
  • 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.

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.
  • 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.

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.
  • 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.

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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.

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 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.
  • 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.
  • 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.
  • 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.

Woody Ornamentals-Conifer

Boxwood (Buxus)

  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

Fir (Abies)

  • 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.
  • 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.
  • 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.

Woody Ornamentals-Deciduous-Shrub

Barberry (Berberis)

  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.

Butterfly bush (Buddleia)

  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

Cotoneaster (Cotoneaster)

  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

Dogwood (Cornus)

  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.

Smoketree (Cotinus)

  • 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.
  • 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.
  • 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.

Woody Ornamentals-Deciduous-Tree

Ash (Fraxinus)

  • 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.

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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

Catalpa (Catalpa)

  • 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.
  • 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.
  • 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.
  • 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.

Crabapple (Malus)

  • 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.

Filbert (Corylus)

  • 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.
  • 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.
  • 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.
  • 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.

Hackberry (Celtis)

  • 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.
  • 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.
  • Downy mildew (Woody plants) (Peronosporaceae family)
  • 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.
  • 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.
  • 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.

Hawthorn (Crataegus)

  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

Redbud (Cercis)

  • 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.
  • 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)
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • 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.
  • 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.
  • 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.
  • 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.

© 2013 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