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.
  • 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.
  • 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.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • 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.
  • 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.
  • 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.
  • 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.
  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • Root rot (Fusarium species (W))
    Symptoms include stunting, chlorosis, root necrosis and death of woody plants. Symptoms are dependent on cultural practices and the local environment.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • 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.
  • 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.
  • 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 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.
  • 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.

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.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • 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.
  • 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.
  • 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)

  • Damping off (Fusarium, Pythium, Rhizoctonia solani)
    Seedlings killed by damping-off initially are healthy, but shortly after emergence, become infected at or just below the soil line. Lower stems of seedlings collapse, seedlings fall over onto the soil surface and subsequently die. Seedlings with damping-off will die and cannot be saved.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • 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.
  • Root rot (woody plants) (Pythium species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Rusts (herbaceous) (Several)
    Symptoms of infection usually first appear as light-colored spots on upper leaf surfaces followed by dry, brown, orange, purple, reddish or yellowish spore masses or pustules commonly on the lower leaf surfaces. Each rust species is specific to a certain host genus or species and cannot spread to unrelated plants. Moderate infections will not harm plants, but can make plants unattractive. Heavily infected leaves may curl, wither and drop prematurely. Severely infected plants may be stunted. Rusts spread primarily via windblown spores.
  • Septoria leaf spot (herbaceous) (Septoria species (H))
    Symptoms first appear at plant bases as small (approx. 1∕4" diameter) spots with whitish centers and dark borders on leaves and stems. Eventually multiple spots on a single leaf will merge, leading to extensive destruction of leaf tissue. Can lead to total defoliation of lower leaves and even death of an infected plant. Septoria persists mainly on crop debris, or on infected plant tissue or seeds and spreads via watersplash.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • 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.
  • 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.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • Phytophthora 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.
  • Impatiens necrotic spot (Impatiens necrotic spot virus (INSV))
    Viruses can only be definitively diagnosed in a lab under high magnification or with various serological test kits. Symptoms can include necrotic streaks, spots, rings and lines on leaves and stems; vein necrosis; distorted flowers, stems and leaves; general stunting; and bud drop. Black, brown, reddish or yellowish concentric rings, although not always present, are also symptoms of viral infection. This virus is spread by thrips which feed on infected plants and spread the virus to healthy plants via their saliva.
  • Phytophthora rot (root, stem or crown-herbaceous) (Phytophthora species (H))
    May cause leaves to discolor, wilt and drop prematurely. Infected plants are stunted, stems die back and the entire plant may be killed. Thrives under wet conditions with similar symptoms on similar hosts often alongside Pythium species. Spreads via watersplash.
  • 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.
  • 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.
  • 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)

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

Fir (Abies)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • 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.
  • Cytospora canker (Cytospora species)
    A stem and branch disorder affecting many different types of conifers. In Wisconsin, Colorado Blue Spruce is the main species that is affected.
  • 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.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.

Hemlock (Tsuga)

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

Juniper (Juniperus)

Pine (Pinus)

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

Spruce (Picea)

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

Woody Ornamentals-Deciduous-Shrub

Barberry (Berberis)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • 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.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

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.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.

Butterfly bush (Buddleia)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • 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.
  • Root rot (woody plants) (Cylindrocladium species)
    Root infections are characterized by many dark brown to black lesions often with longitudinal cracks. Severe root disease leads to stunting, wilting, yellowing and death. Stem infections of both conifers and broadleaves arise at the leaf bases and may girdle small stems. Diseased conifer needles turn yellow or red-brown. Dark lesions form in the leaves of broadleaf plants. Leaf blight leads to defoliation.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • 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)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • 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.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Rhizoctonia web blight (Rhizoctonia species (H))
    This disease is favored by high temperatures and high humidity, especially in the greenhouse setting. Symptoms appear as irregular, brown spots which can form anywhere on foliage or stems. In high humidity, web-like brown mycelium can cover infected portions of the plant host. Rhizoctonia is a soil-borne pathogen.
  • Root rot (Fusarium species (W))
    Symptoms include stunting, chlorosis, root necrosis and death of woody plants. Symptoms are dependent on cultural practices and the local environment.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Rhizoctonia species (W))
    Symptoms on the above ground parts of larger plants include necrotic spots and blotches on the leaves, shoot blight and dieback.
  • 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)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • 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.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (Fusarium species (W))
    Symptoms include stunting, chlorosis, root necrosis and death of woody plants. Symptoms are dependent on cultural practices and the local environment.
  • Root rot (woody plants) (Cylindrocladium species)
    Root infections are characterized by many dark brown to black lesions often with longitudinal cracks. Severe root disease leads to stunting, wilting, yellowing and death. Stem infections of both conifers and broadleaves arise at the leaf bases and may girdle small stems. Diseased conifer needles turn yellow or red-brown. Dark lesions form in the leaves of broadleaf plants. Leaf blight leads to defoliation.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • 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.

Honeysuckle (Lonicera)

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

Lilac (Syringa)

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

Privet (Ligustrum)

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

Quince (Chaenomeles)

  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • 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.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.

Rhododendron (Rhododendron)

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

Rose (Rosa)

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

Smoketree (Cotinus)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • 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.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Spiraea (Spiraea)

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

Sumac (Rhus)

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

Viburnum (Viburnum)

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

Weigela (Weigela)

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

Woody Ornamentals-Deciduous-Tree

Ash (Fraxinus)

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

Birch (Betula)

  • Animal damage ()
    Animals that do the most damage to herbaceous plants include: deer, rabbits and woodchucks. Deer damage is distinctive because deer only have teeth on their lower jaws, so when they bite down, they must tear the plant to pull off leaves. Thus, deer damage to plants is rough or shredded-looking. It may also be several feet off of the ground. Plus, if a large amount of plant material is damaged overnight, you should suspect deer. Rabbit damage looks like someone used a pruner to cut the plant off at a clean, 45-degree angle. Woodchucks will mow down plants, or sometimes just nibble on succulent material. They are diurnal, so keep on the lookout.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • 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.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.

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.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • 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.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (Fusarium species (W))
    Symptoms include stunting, chlorosis, root necrosis and death of woody plants. Symptoms are dependent on cultural practices and the local environment.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Pythium species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Rhizoctonia species (W))
    Symptoms on the above ground parts of larger plants include necrotic spots and blotches on the leaves, shoot blight and dieback.
  • Root rot (woody plants) (Thielaviopsis species (W))
    Uncommonly damages woody plants in the landscape. Symptoms include stunting, sparse foliage, poor foliar color and die back after the death of fibrous roots
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Catalpa (Catalpa)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (woody plants) (Thielaviopsis species (W))
    Uncommonly damages woody plants in the landscape. Symptoms include stunting, sparse foliage, poor foliar color and die back after the death of fibrous roots
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Coffeetree (Gymnocladus)

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

Elm (Ulmus)

  • Dutch elm disease (Ophiostoma novo-ulmi)
    Wilting leaves, often on a single branch, are the first symptoms of Dutch elm disease. Yellowing of leaves and leaf drop follow. Trees may quickly lose all of their leaves, or trees may survive several years with an infection localized in a single branch. Infected branches often have brown streaks under the bark that follow the wood grain.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Filbert (Corylus)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • 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.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.

Hackberry (Celtis)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Black walnut toxicity (herbaceous) ()
    Plants sensitive to juglone, a toxic substance produced by black walnut trees and to a lesser extent, butternut trees and shagbark hickories, may be stunted, have yellow or brown twisted leaves, may exhibit wilting or some or all of the plant parts, and die over time. Often an affected plant's vascular tissue will be discolored. Symptoms may occur rapidly, even within a few days of being transplanted into a walnut tree's root zone. Some plants may survive for years near a young walnut tree, only to succumb as the tree increases in size.
  • 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.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.

Hawthorn (Crataegus)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • 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.
  • Cytospora canker (Cytospora species)
    A stem and branch disorder affecting many different types of conifers. In Wisconsin, Colorado Blue Spruce is the main species that is affected.
  • Girdling ()
    Decline and dieback caused by girdling, either by roots or man-made objects, usually affect mature trees moreso than young ones. Symptoms may include: thinning crown, leaf scorch, sparse foliage, leaves in tufts, branch dieback, early fall color, and leaf drop.
  • Gray mold (Botrytis blight) (Botrytis cinerea)
    Causes brown, water-soaked spots or decay on leaves or petals. Once diseased tissue encircles the stem, the shoot will wilt. Botrytis is easily diagnosed by the fluffy gray, tan or brown mold produced on blighted plant parts under moist conditions. It rapidly blights flowers. Infected petals that fall onto foliage or stems can cause additional blighting and dieback.
  • Herbicide Damage ()
    Herbicides can damage any type of plant and injury usually happens as a result of drift, careless application or evaporation during hot weather. Symptoms of herbicide injury may include: twisted plant stems; stem fasciation; narrow, curling or leathery leaves; or excessive callus formation on roots and stems along with secondary root growth. At extremely low application rates, broadleaf herbicides such as 2,4-D, MCPP or dicamba usually will not kill plants, although they will act as growth regulators.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • 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.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • 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.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • 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.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Mealybug (Pseudococcidae family)
    Characteristically mealybugs are covered in white granular or cotton-like wax. Mealy bug bodies are always soft and the females are oval and flat with distinct segmentation often visible in the wax. Eggs are usually laid in a white cottony material underneath the female. Widespread in greenhouses and indoor plants; not an outdoor problem. Depending on temperature, one generation can develop every 1-3 months.
  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (woody plants) (Cylindrocladium species)
    Root infections are characterized by many dark brown to black lesions often with longitudinal cracks. Severe root disease leads to stunting, wilting, yellowing and death. Stem infections of both conifers and broadleaves arise at the leaf bases and may girdle small stems. Diseased conifer needles turn yellow or red-brown. Dark lesions form in the leaves of broadleaf plants. Leaf blight leads to defoliation.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.

Honeylocust (Gleditsia )

  • Nectria canker (Nectria (Neonectria))
    Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.

Locust (Robinia)

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

Magnolia (Magnolia)

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

Maple (Acer)

  • Animal damage ()
    Animals that do the most damage to herbaceous plants include: deer, rabbits and woodchucks. Deer damage is distinctive because deer only have teeth on their lower jaws, so when they bite down, they must tear the plant to pull off leaves. Thus, deer damage to plants is rough or shredded-looking. It may also be several feet off of the ground. Plus, if a large amount of plant material is damaged overnight, you should suspect deer. Rabbit damage looks like someone used a pruner to cut the plant off at a clean, 45-degree angle. Woodchucks will mow down plants, or sometimes just nibble on succulent material. They are diurnal, so keep on the lookout.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Cold/Frost Damage ()
    Any part of a plant may be affected by cold damage. In spring, it's usually tender growth, which will appear watersoaked and may turn black. Flower buds can sustain damage during winter dormancy or during the blooming period. Plants will either have reduced numbers of blooms, and hence fruit set, or won't bloom at all. In fall, if plants aren't hardened off, they can sustain cold injury in temperatures well above those tolerated by acclimated plants. Root injury is rare unless plants are in raised beds or containers. Generally younger plants are more susceptible than mature plants. Cold injury on woody plants usually presents in the form of frost cracks in wood or bark. Mature leaves may turn red, purple, brown or black and may or may not fall off the tree or shrub.
  • 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.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Pythium species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Rhizoctonia species (W))
    Symptoms on the above ground parts of larger plants include necrotic spots and blotches on the leaves, shoot blight and dieback.
  • Root rot (woody plants) (Thielaviopsis species (W))
    Uncommonly damages woody plants in the landscape. Symptoms include stunting, sparse foliage, poor foliar color and die back after the death of fibrous roots
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Oak (Quercus)

  • Oak wilt (Ceratocystis fagacearum)
    Initially, single branches on infected trees wilt and die. Leaves on these branches often bronze, or turn tan or dull green, starting at the tips or outer margins. Leaves may also droop, curl, or fall from the tree. Infected trees eventually die. Oak wilt can kill oaks in the red oak group in less than one month. Oaks in the white oak group usually have less severe symptoms and are rarely killed in one season.

Plum / Cherry (Prunus)

  • Black knot (Apiosporina morbosa)
    During the first year of infection, black knot-infected trees develop greenish-brown to brown swellings on affected branches and trunks. During the second year, these swellings enlarge into the ugly, black, erupting tumors (galls) characteristic of the disease. Older gall tissue (greater than two years old) often dies and then is colonized by fungi that give the gall a whitish or pinkish color. Severe black knot infections may cause general tree decline or death if galls girdle large limbs or tree trunks.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Redbud (Cercis)

  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • Birch canker (Nectria (Neonectria) galligena)
    Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch.
  • 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.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (woody plants) (Cylindrocladium species)
    Root infections are characterized by many dark brown to black lesions often with longitudinal cracks. Severe root disease leads to stunting, wilting, yellowing and death. Stem infections of both conifers and broadleaves arise at the leaf bases and may girdle small stems. Diseased conifer needles turn yellow or red-brown. Dark lesions form in the leaves of broadleaf plants. Leaf blight leads to defoliation.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Russian Olive (Elaeagnus )

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

Serviceberry (Amelanchier)

  • Animal damage ()
    Animals that do the most damage to herbaceous plants include: deer, rabbits and woodchucks. Deer damage is distinctive because deer only have teeth on their lower jaws, so when they bite down, they must tear the plant to pull off leaves. Thus, deer damage to plants is rough or shredded-looking. It may also be several feet off of the ground. Plus, if a large amount of plant material is damaged overnight, you should suspect deer. Rabbit damage looks like someone used a pruner to cut the plant off at a clean, 45-degree angle. Woodchucks will mow down plants, or sometimes just nibble on succulent material. They are diurnal, so keep on the lookout.
  • Armillaria root rot (Armillaria species)
    Also known as shoestring root rot, this is an often lethal disease of woody plant roots and lower stems. It can affect almost any conifer or hardwood species, from seedling to maturity. Trees and shrubs stressed due to drought or defoliation are more susceptible. The fungi produce tough, cord-like strands called “rhizomorphs” that grow from decaying stumps and roots through the soil. Infection of other trees or shrubs can result from penetration of intact roots by rhizomorphs. In late summer or early fall, honey-colored mushrooms of Armillaria fungi develop near the bases of colonized plants and produce spores that are distributed by wind. Infection also can occur after these spores germinate in wounds on stems or roots. Above-ground symptoms include slow growth, yellowing and dwarfing of foliage, and thin crowns. Dieback of twigs and branches also may occur. Symptoms may develop slowly and intensify over many years or kill their host rapidly. Bark on lower stems or roots may be killed and crack, with flow of resin common on conifers. Thin white mats of fungus tissue called “mycelial fans” may be present within and beneath killed bark. Stem and root wood decayed by Armillaria fungi is often water-soaked, creamy to yellow in color, and spongy or stringy in texture. Rhizomorphs are commonly seen on or beneath the bark and growing from decayed stumps and roots.
  • Armored scale (Diaspididae family)
    Armored scales are oval, somewhat elongate (think oyster shell), small (1/20-1/8") insects that secrete a hard, waxy cover. During the adult stage, no body parts are visible except the cover. Eggs are laid under the cover and hatch into crawlers, which can move around and are susceptible to sprays and oils.
  • 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.
  • Planting Too Deeply ()
    Trees planted too deeply in the soil exhibit a gradual decline in their growth and development. Deep planting acts as a primary stress factor and can lead to stem girdling roots which will eventually choke the trunk. It can also make trees more susceptible to disease and insect pests, and frost cracks; can cause roots to grow up toward the surface where they will have to compete for nutrients and water; and can activate suckering shoots or adventitious roots that grow from the underground part of the trunk. If you cannot see the root flare of your woody plant, then it is planted too deeply.
  • Root rot (Fusarium species (W))
    Symptoms include stunting, chlorosis, root necrosis and death of woody plants. Symptoms are dependent on cultural practices and the local environment.
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Pythium species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Rhizoctonia species (W))
    Symptoms on the above ground parts of larger plants include necrotic spots and blotches on the leaves, shoot blight and dieback.
  • Root rot (woody plants) (Thielaviopsis species (W))
    Uncommonly damages woody plants in the landscape. Symptoms include stunting, sparse foliage, poor foliar color and die back after the death of fibrous roots
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • Sunscald ()
    Often the first symptom of sunscald is the reddish-brown discoloration of bark. Then, the bark shrinks, appearing sunken, splits and peels back in chunky patches exposing sapwood underneath. Often cankers develop. Severe sunscald may cause the entire trunk to be girdled, or only individual branches. Look for sunscald on the south, southwest or west side of trunks or branches. It most commonly affects trees suffering from water stress or young trees with thin bark. Newly planted or transplanted are most susceptible and container-grown plants are more likely to get sunscald than field-grown ones. Species particularly prone to sunscald include: Liriodendron, Acer, Tilia, Prunus, Pyrus, Malus, Juglans, and Ulmus.
  • Verticillium wilt (woody plants) (Verticillium species (W))
    The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.

Tuliptree (Liriodendron )

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

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.
  • 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.
  • Leaf scorch (Colletotrichum species)
    Caused by one of the fungi that causes anthracnose, leaf scorch usually appears on previously injured tissue in hot, humid weather. There may also be symptoms on stems. The disease will not move to healthy tissue. Symptoms include bleached, brown, or scorched tissue on leaves or stems, with small (pinhead-sized) masses of clear to yellowish spores (use a hand lens).
  • Root rot (woody plants) (Phytophthora species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggestareardenersadners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Pythium species (W))
    Gardeners often become aware of root rot problems when they see above ground symptoms of the disease. Plants with root rot are often stunted or wilted, and may have leaves with a yellow or red color, suggesting a nutrient deficiency. Examination of the roots of these plants reveals tissue that is soft and brown.
  • Root rot (woody plants) (Rhizoctonia species (W))
    Symptoms on the above ground parts of larger plants include necrotic spots and blotches on the leaves, shoot blight and dieback.
  • Root rot (woody plants) (Thielaviopsis species (W))
    Uncommonly damages woody plants in the landscape. Symptoms include stunting, sparse foliage, poor foliar color and die back after the death of fibrous roots
  • Slug (Order Sytlomatophora)
    Garden slugs are terrestrial mollusks, essentially snails without shells. As they move, they coat surfaces with a silvery, slimy substance. Most feed at night or during dark, cloudy days. Trails and feeding injuries are usually noticed before the slug itself. Slugs overwinter either as adults or as eggs. They become active during the first warm days of spring, and thrive under cool, damp conditions. Populations will be high during/following damp, rainy weather, and will almost disappear during dry periods. Slugs cannot survive direct sunlight. Rock walls, boards, pots and plant debris, as well as shaded flower beds and heavily mulched gardens, serve as ideal daytime resting sites.
  • Soft scale (Coccidae family)
    Soft scales are usually broadly oval becoming larger and more humped as eggs mature underneath the protective cover. Look for adults on twigs or small branches and immature stages on leaves or needles.
  • Soil Compaction ()
    Soil compaction is usually one of several factors that can lead to the decline of woody plants. It is a physical factor, much like drought, freezing or mechanical damage. When combined with chemical factors such as salinity, nutrient imbalances, soil acidification, herbicides or pollution and biotic factors, such as disease or insect problems, the tree will often go into slow decline. Remove any one of these factors before the plant dies or is beyond help, and the decline can be arrested and the plant may recover. Symptoms of soil compaction vary with tree species and cause, but they can include: slow growth; small, distorted, sparse, chlorotic and nutrient-deficient leaves; scorch; premature autumn color; premature leaf drop; abnormally large "distress" crops of fruit; insufficient storage of food reserves for winter; and dieback of twigs or branches. The three factors that lead to soil compaction are gravity, rain and traffic.
  • Sooty molds (Several)
    Sooty molds are dark fungi that grow on plant surfaces covered in honeydew excreted by insects with piercing/sucking mouth parts such as aphids, scale, mealybugs and whiteflies. It is generally harmless to plants, except when it is prolific, preventing light from reaching leaf surfaces, causing plants stress. This stress may make the plant more susceptible to other diseases or problems.
  • 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