Green Industry - A Knowledge Portal for Commercial Horticulture in Wisconsin (sponsored by University of Wisconsin-Extension)
Diagnostics - Woody Ornamentals
Woody Ornamentals-Conifer
Arborvitae (Thuja)
- Arborvitae leafminer (Argyresthia species)
Mature larvae are approximately 6 mm long with greenish brown bodies and a black head. Adults are silvery gray moths. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown. - Shothole borer (Scolytus rugulosus)
Borers are small 1/10th inch gray-black beetles. - Spruce spider mite (Oligonychus ununguis)
Mites are 0.5 mm long with eight legs. Green or dark red in color.
Boxwood (Buxus)
- Verticillium wilt (Verticillium )
The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
Douglas fir (Pseudotsuga)
- Cooley Spruce gall adelgid (Adelges cooleyi)
Closely resembles aphids. Adelgids are 1 mm long, and dark brown to black in color. Adults secrete white curled waxy strands to cover their bodies. - Eastern Spruce gall adelgid (Adelges abietis)
Closely resembles aphids with a body that is 1mm long, and dark brown to black in color. Adults secrete white curled waxy strands to cover their bodies. - White-marked tussock moth (Orygia leucostigma)
Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths. - Woolly adelgids (Several)
A family of woolly aphids that are associated with conifers. These are not true aphids but similar to woolly aphids in that their bodies are covered in white, cottony, wax-like threads that cause them to appear wooly. - Woolly aphids (Several)
Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.
Fir (Abies)
- Balsam gall midge (Paradiplosis tumifex)
Insects are tiny delicate flies which deposit their eggs on the terminal buds of conifers. Upon hatching tiny white larvae migrate to the bases of newly forming needles and burrow into needle tissue. - Balsam twig aphid (Mindarus abietus)
Mature aphids are bluish gray and approximately 1.8 mm long - Cytospora canker (Cytospora species)
Cytospora canker usually first appears on lower branches and progresses up the tree. Individual upper branches may show symptoms as well. Needles on infected branches turn purple, then brown and die. Diseased needles eventually fall off and the infected branch dies. Infected branches often produce a bluish-white sap that oozes somewhere along their length. - Swiss needlecast (Phaeocryptopus gaeumannii)
Infected needles of Douglas fir become discolored, turning a blotchy yellow-green or yellow, and then browning from the tips. Older needles are more severely affected than younger needles. Brown needles drop prematurely, leaving twigs with only the newest growth. Using a hand lens, small, black reproductive structures of the Swiss needlecast fungus can be seen in two diffuse bands on the undersurface of infected needles. - White pine weevil (Pissodes strobi)
Adult weevils are 6 mm long with a long snout and oval body which is brown with brown and white spots on the back. There may also be some lateral die back due to larval feeding. - White-marked tussock moth (Orygia leucostigma)
Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.
Hemlock (Tsuga)
- Cytospora canker (Cytospora species)
Cytospora canker usually first appears on lower branches and progresses up the tree. Individual upper branches may show symptoms as well. Needles on infected branches turn purple, then brown and die. Diseased needles eventually fall off and the infected branch dies. Infected branches often produce a bluish-white sap that oozes somewhere along their length.
Juniper (Juniperus)
- Cedar-rosaceous Rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance. - Juniper scale (Carulaspis juniperi)
Both male and female scales are creamy white. Females are 1.5 mm in diameter while male juniper scale is slightly smaller and oval in shape. - Phomopsis twig blight (Phomopsis juniperovora)
Initially, small gray lesions (spots) form on the terminal four to six inches of new shoots in early spring. Infected branches typically first turn dull red or brown, and finally ash-gray as lesions expand to girdle and kill branch tips. Small, black pycnidia (the reproductive structures of the causal fungus) can easily be seen on dead branches with the unaided eye or with a hand lens. Severe infections may result in death of an entire plant. - Shothole borer (Scolytus rugulosus)
Borers are small 1/10th inch gray-black beetles.
Pine (Pinus)
- Brown Spot (Mycosphaerella dearnessii)
Similar to Lophodermium needlecast. This disease first appears as bar like gray-black spots which turn brown with yellow margins before they are detected. Later the entire needle turns yellow, then brown and may fall off. Older trees show most infection at ground level, with the disease progressing upward. Older needles on the branch are most likely to show symptoms. Infection by Brown Spot most often occurs in August and September. Needles then die back and turn brown. - Cytospora canker (Cytospora species)
Cytospora canker usually first appears on lower branches and progresses up the tree. Individual upper branches may show symptoms as well. Needles on infected branches turn purple, then brown and die. Diseased needles eventually fall off and the infected branch dies. Infected branches often produce a bluish-white sap that oozes somewhere along their length. - Dothistroma needle blight (Dothistroma septosporum)
Dothistroma needle blight first appears as dark green, water-soaked spots on the needles. The spots become tan, yellow, or reddish-brown, and may encircle the needles to form bands. The tip of the needle beyond the band eventually dies leaving the base of the needle alive and green. Young trees are more likely to suffer damage than older trees. Seedlings (<1 yr. old) can be killed within a year after infection. - Eastern pine shoot borer (Eucosoma gloriola)
Larvae up to 13 mm in length are off white to gray with yellowish brown heads. Adults have a copper red color with two gray bands on the forewings. - European pine sawfly (Neodiprion sertifer)
Larvae are gray green with black heads and legs. They have a light green stripe down the back and two light green and one dark green to black stripe on each side. Larvae are 18 - 25 mm long when mature. - European pine shoot moth (Rhyacionia buoliana)
Larvae are brown with a black head and legs and 18 mm long when mature. Adults are rusty red moths. - Introduced pine sawfly (Diprion similis)
Larvae have a black head and a yellow-green body with a black double stripe down the back and many yellow spots. Approximately 24 mm in length with three pairs of thoracic legs and 8 pairs of abdominal prolegs. Adult sawflies are 4-7 mm long. - Lophodermium needlecast (Lophodermium)
Similar to Brown Spot. First appears as bar like gray-black spots turning brown with yellow margins before they are detected. Later the entire needle turns yellow, then brown and may fall off. Older trees show most infection at ground level, with the disease progressing upward. Older needles on the branch are most likely to show symptoms. Damage is most often noticed in the Spring. - Pine needle miner (Zelleria haimbachi)
Adult female scales are white, teardrop shaped and 2.5 - 3 mm long. - Pine needle scale (Chionaspis pinifoliae)
Crawlers are amber colored. Adult scale is gray to black. - Pine tortoise scale (Toumeyella parvicornis)
Females are reddish brown, 4-7mm long and convex. - Redheaded pine sawfly (Neodiprion lecontei)
Larvae are up to 30 mm long with reddish brown heads and yellow bodies with 6 rows of irregular black spots. Adults are brownish and wasp like. - Shothole borer (Scolytus rugulosus)
Borers are small 1/10th inch gray-black beetles. - Sphaeropsis (Diplodia) pine tip blight (Sphaeropsis sapinea)
Initially you may notice branch tips that ooze a large amount of resin. Eventually, these branch tips brown and die. Often, the newest needles on these dead branches will be of different lengths. As the disease progresses, sunken or swollen, discolored areas (called cankers) may form on infected twigs. Heavy resin flow and an absence of tunnels help distinguish Sphaeropsis shoot blight and canker from damage caused by insect pests. - White pine weevil (Pissodes strobi)
Adult weevils are 6 mm long with a long snout and oval body which is brown with brown and white spots on the back. There may also be some lateral die back due to larval feeding. - Woolly adelgids (Several)
A family of woolly aphids that are associated with conifers. These are not true aphids but similar to woolly aphids in that their bodies are covered in white, cottony, wax-like threads that cause them to appear wooly. - Woolly aphids (Several)
Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly. - Zimmerman pine moth complex (Dioryctria zimmermani)
Mature larvae are up to 25 mm long, dirty white and occasionally have pale pink or pale green coloration. Bodies have black spots on the abdomen and their heads are also black. Adults are moths.
Spruce (Picea)
- Cooley Spruce gall adelgid (Adelges cooleyi)
Closely resembles aphids. Adelgids are 1 mm long, and dark brown to black in color. Adults secrete white curled waxy strands to cover their bodies. - Cytospora canker (Cytospora species)
Cytospora canker usually first appears on lower branches and progresses up the tree. Individual upper branches may show symptoms as well. Needles on infected branches turn purple, then brown and die. Diseased needles eventually fall off and the infected branch dies. Infected branches often produce a bluish-white sap that oozes somewhere along their length. - Eastern Spruce gall adelgid (Adelges abietis)
Closely resembles aphids with a body that is 1mm long, and dark brown to black in color. Adults secrete white curled waxy strands to cover their bodies. - Rhizosphaera needlecast (Rhizosphaera kalkhoffii)
The first noticeable sign of Rhizosphaera needlecast is a loss of the inner-most needles on the lower branches of spruce trees. Often the youngest needles remain healthy. If your tree has this pattern of needle loss, use a 10X hand lens to observe the shed needles. If Rhizosphaera needlecast is the problem, you should be able to see rows of small black dots erupting through the surface of the needle. These black dots are fruiting bodies of the fungus that causes the disease and are diagnostic. - Spruce needle miner (Endothenia albolineana)
Larvae are light greenish brown caterpillars with a dark head and about 10 mm in length. - Spruce spider mite (Oligonychus ununguis)
Mites are 0.5 mm long with eight legs. Green or dark red in color. - White pine weevil (Pissodes strobi)
Adult weevils are 6 mm long with a long snout and oval body which is brown with brown and white spots on the back. There may also be some lateral die back due to larval feeding. - Woolly aphids (Several)
Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly.
Yew (Taxus)
- Black vine weevil (Otiorhynchus sulcatus)
Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 9-13 mm long, black with gold flecks. - Taxus mealybug (Phenacoccus acericola)
A small soft bodied insect covered with fine whitish wax, similar in appearance to soft scale.
Woody Ornamentals-Deciduous-Shrub
Barberry (Berberis)
- Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown. - Verticillium wilt (Verticillium )
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.
Cotoneaster (Cotoneaster)
- Fire blight (Erwinia amylovora)
Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown. - Oystershell scale (Lepidosaphes ulmi)
Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax. - San Jose scale (Quadraspidiotus perniciosus)
Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
Dogwood (Cornus)
- Anthracnose (Several)
Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected. - Oystershell scale (Lepidosaphes ulmi)
Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax. - San Jose scale (Quadraspidiotus perniciosus)
Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
Euonymus (Euonymus)
- Black vine weevil (Otiorhynchus sulcatus)
Larvae are 12.5 mm long, C-shaped, legless and creamy white in color with a brown head. Adults are 9-13 mm long, black with gold flecks. - Euonymus caterpillar (Yponomeuta cagnagella)
Larvae are light greenish yellow in color with two sets of black spots on each body segment. Fully grown larvae reach 20mm in length. - Euonymus scale (Unaspis euonymi)
Adult female scales have a dark brown oyster shaped cover about 3 mm long and are usually found on twigs. Male scales are smaller, fuzzy white, elongated and commonly found on foliage. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
Forsythia (Forsythia)
- San Jose scale (Quadraspidiotus perniciosus)
Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
Honeysuckle (Lonicera)
- Verticillium wilt (Verticillium )
The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
Lilac (Syringa)
- Ash borer (lepidoptera - clearwing moth) (Podosesia syringae)
Larvae are creamy white grubs with a small dark head, small prolegs on the abdomen with hook like crochets at the tip. - Bacterial leaf spot & twig blight (Pseudomonas syringae pv. Syringae)
Initial symptoms of bacterial blight may include dark brown necrotic (dead) leaf spots with yellow margins. If leaf spots develop before leaves are fully expanded, leaf curling and twisting may result. More advanced symptoms include necrotic blotches starting at the leaf margins and advancing inward, as well as black streaking on twigs. In its' most severe form, bacterial blight can result in the death of branch tips, leaves and blossoms. - Lilac borer (Podosesia syringae)
Larvae are creamy white grubs with small dark heads and small prolegs on the abdomen with hook-like crochets at the tip. - Verticillium wilt (Verticillium )
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)
- Privet thrips (Dendrothrips ornatus)
Adults are generally brown with thin light bands on each abdominal segment. - San Jose scale (Quadraspidiotus perniciosus)
Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow. - Verticillium wilt (Verticillium )
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)
- Cedar-rosaceous Rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance. - Fire blight (Erwinia amylovora)
Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown.
Rhododendron (Rhododendron)
- Verticillium wilt (Verticillium )
The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
Rose (Rosa)
- Fire blight (Erwinia amylovora)
Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown. - San Jose scale (Quadraspidiotus perniciosus)
Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow. - Verticillium wilt (Verticillium )
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)
- Peachtree borer (Synanthedon exitiosa)
Larvae are creamy white with a reddish brown head. - Verticillium wilt (Verticillium )
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)
- Fire blight (Erwinia amylovora)
Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown. - Verticillium wilt (Verticillium )
The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
Sumac (Rhus)
- Cottony maple scale (Pulvinaria innumerabilis)
Flat and pale brown to dark brown, Scales form protruding white egg sacs which are over 1/4th of an inch when the egg mass swells. - Verticillium wilt (Verticillium )
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 (Verticillium )
The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash. - Viburnum crown borer (Synanthedon viburni)
Adults of both species are day flying moths that mimic the flight and appearance of wasps. They are bluish black with yellow markings, clear wings and a wingspan of 3/4 inch. Larvae are pinkish white caterpillars with reddish brown heads. During late and June and July, adults emerge from infested plants and deposit eggs on bark near wound sites. Larvae tunnel in the bark and cambium but do not enter the wood. Over time this will cause distortions and swellings on the main stems and branches.
Weigela (Weigela)
- Verticillium wilt (Verticillium )
The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
Woody Ornamentals-Deciduous-Tree
Ash (Fraxinus)
- Anthracnose (Several)
Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected. - Ash borer (lepidoptera - clearwing moth) (Podosesia syringae)
Larvae are creamy white grubs with a small dark head, small prolegs on the abdomen with hook like crochets at the tip. - Ash flower gall mite (Eriophyes fraxiniflora)
Adult gall mites are carrot shaped with two pairs of legs but not easily visible without a microscope. - Ash plantbug (Tropidosteptes amoenus)
Yellow or brown to black in color with yellow to pink markings with a length of 5-6 mm. - Emerald ash borer (Agrilus planipennis)
Larvae are 26-32 mm long, creamy white with triangular segments and a brownish head. Adults are 13 mm long with a metallic green color. - Fall webworm (Hyphantria cunea)
Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown. - Lilac borer (Podosesia syringae)
Larvae are creamy white grubs with small dark heads and small prolegs on the abdomen with hook-like crochets at the tip. - Mountain-ash sawfly (Pristophora geniculata)
Adult sawflies are 9 mm long, black and look similar to wasps. Larvae are up to 20 mm long with pale green to yellow bodies with black spots and a blue or orange head. - Oystershell scale (Lepidosaphes ulmi)
Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax. - Scab (Venuria inaequalis)
Scab lesions (diseased areas) are often first noticed on leaves, where they most commonly occur on the upper leaf surface. Fruits are also very susceptible to infection. Lesions on both leaves and fruits are roughly circular with feathery edges, and have an olive green to black color. They can be as small as the size of a pinhead or as large a 1/2 inch in diameter. When the disease is severe, lesions can merge and cover a large portion of the leaf or fruit surface. Defoliation of the tree often follows. - Verticillium wilt (Verticillium )
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)
- Anthracnose (Several)
Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected. - Birch canker (Nectria (Neonectria) galligena)
Canker lesions first appear as small dark depressed areas on young, smooth barked stems, often killing twigs by girdling. Most cankers are centered on small branch stubs or their remains. Diseased trees usually have more than one canker. This disease is among the most important stem diseases on birch. - Birch leaf skeletonizer (Bucculatrix canadensisella)
Larvae are pale yellow, sometimes tinted with green and approximately 7mm long. White webs or cocoons may also be present on the undersides of leaves. - Birch leafminer (Fenusa pusilla)
Mature mining larvae are 6 mm long, yellowish white in color and flattened. Adults are small, black, thick wasted wasps with yellowish legs. - Bronze birch borer (Agrilus anxius)
Adults are flattened with antennae 1/4th their body length. Borers are 6-11 mm in length and olive black in color with coppery reflections. Larvae are 25 mm long, flat headed. - Fall webworm (Hyphantria cunea)
Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown. - White-marked tussock moth (Orygia leucostigma)
Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.
Buckeye (Aesculus)
- Anthracnose (Several)
Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected. - Verticillium wilt (Verticillium )
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)
- Verticillium wilt (Verticillium )
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 (Verticillium )
The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
Crabapple (Malus)
- Anthracnose (Several)
Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected. - Cankerworms (Alsophila pometaria)
Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner. Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs. - Cedar-rosaceous Rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance. - Eastern tent caterpillar (Malacosoma americanum)
Larvae grow to greater than 25 mm in length. Caterpillars have black heads with a white stripe down the length of the back and a yellow stripe on each side with blue markings. - Fall webworm (Hyphantria cunea)
Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots. - Fire blight (Erwinia amylovora)
Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown. - Oystershell scale (Lepidosaphes ulmi)
Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax. - San Jose scale (Quadraspidiotus perniciosus)
Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow. - Scab (Venuria inaequalis)
Scab lesions (diseased areas) are often first noticed on leaves, where they most commonly occur on the upper leaf surface. Fruits are also very susceptible to infection. Lesions on both leaves and fruits are roughly circular with feathery edges, and have an olive green to black color. They can be as small as the size of a pinhead or as large a 1/2 inch in diameter. When the disease is severe, lesions can merge and cover a large portion of the leaf or fruit surface. Defoliation of the tree often follows. - Shothole borer (Scolytus rugulosus)
Borers are small 1/10th inch gray-black beetles. - White-marked tussock moth (Orygia leucostigma)
Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths. - Woolly adelgids (Several)
A family of woolly aphids that are associated with conifers. These are not true aphids but similar to woolly aphids in that their bodies are covered in white, cottony, wax-like threads that cause them to appear wooly. - Woolly aphids (Several)
Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly. - Yellow-necked caterpillar (Datana ministra)
Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.
Elm (Ulmus)
- Cankerworms (Alsophila pometaria)
Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner. Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs. - Dutch elm disease (Ophiostoma novo-ulmi)
Wilting leaves, often on a single branch, are the first symptoms of Dutch elm disease. Yellowing of leaves and leaf drop follow. Trees may quickly lose all of their leaves, or trees may survive several years with an infection localized in a single branch. Infected branches often have brown streaks under the bark that follow the wood grain. - Elm leaf beetle (Pyrrhalta luteola)
Adult beetles are 5-7 mm long and yellow to dullish green with a black stripe at the edge of each wing cover. There are three dark spots behind the head. Larvae are up to 12 mm in length, yellowish in color with two lines of black dots along the back. - Elm leafminer (Kaliofenusa ulmi)
Mature larvae are 45 mm long, wrinkled and yellowish to greenish white with a median black stripe and many whitish stripes that makes its skin appear grainy. - Elm sawfly (Cimbex americana)
Larvae are pale yellow to green in color with a dark stripe down the back, which develops a pebbly skin when full grown. - Fall webworm (Hyphantria cunea)
Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots. - Spiny elm caterpillar (Nymphalis antiopa)
Dark colored caterpillar with purple markings. Adult is the Morning Cloak Butterfly. - Verticillium wilt (Verticillium )
The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash. - Yellow-necked caterpillar (Datana ministra)
Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.
Filbert (Corylus)
- Oystershell scale (Lepidosaphes ulmi)
Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax.
Hackberry (Celtis)
- Hackberry nipple gall (Pachypsylla celtidismamma)
Adults are psylliads that resemble miniature cicadas. Mottled light brown in color, 4-5 mm long with wings that peak over the back. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown.
Hawthorn (Crataegus)
- Cedar-rosaceous Rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance. - Fire blight (Erwinia amylovora)
Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown. - Lace bugs (Tingidae species)
Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown. - San Jose scale (Quadraspidiotus perniciosus)
Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow. - Woolly adelgids (Several)
A family of woolly aphids that are associated with conifers. These are not true aphids but similar to woolly aphids in that their bodies are covered in white, cottony, wax-like threads that cause them to appear wooly. - Woolly aphids (Several)
Multiple species of aphids characterized by covering their bodies in long waxy threads that cause them to appear wooly. - Yellow-necked caterpillar (Datana ministra)
Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.
Hickory (Carya)
- Anthracnose (Several)
Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected. - Fall webworm (Hyphantria cunea)
Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots. - Hickory leaf stem gall phylloxera (Pylloxera caryaecaulis)
Closely related to aphids. Species is usually identified by gall formation. - Walnut caterpillar (Datana integerrina)
Larvae are 50 mm long when mature and gray to black with long hairs. Younger larvae are reddish brown with light yellow stripes down the length of their bodies. Adults are stout bodied moths.
Honeylocust (Gleditsia )
- Honey locust plantbug (Diaphnocoris chlorionis)
Adults are winged pale green and 5-6 mm in length. Nymphs are a smaller version of the adults with short wing buds. - Honey locust podgall midge (Dasineura gleditschiae)
Adults are tiny midges generally black with a reddish abdomen. Larvae are cream colored maggots found in the pod galls. - Honey locust spider mite (Platytetranychus multidigituli)
Tiny (1 mm) orange mite, turning pale yellow to green as they mature. - Leafhoppers (Several)
3-15 mm in length, wedge shaped with wings that peak over their backs. Nymphs are wingless but active and move readily when disturbed. Adults are winged and fly readily when disturbed. - Nectria canker (Nectria (Neonectria))
Nectria canker is characterized by the production of sore-like wounds (cankers) that form on twigs, branches, and trunks. Cankers can form at leaf scars and wherever injuries occur. Injuries can be caused by pruning (particularly improper pruning), frost, hail, cracking from heavy snow or ice, sunscald, insects, or mammals. Cankers appear first as slightly sunken areas on the bark, but can grow for years, becoming target-shaped or elongated. Small branches girdled by cankers can wilt suddenly, fail to leaf out, and die.
Linden (Tilia)
- Cankerworms (Alsophila pometaria)
Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner. Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs. - Fall webworm (Hyphantria cunea)
Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown. - Linden borer (Saperda vestia)
Primary color is olive green to yellow brown because of hairs covering the dark colored body. Most have dark spots on each wing cover, two above the middle of the wing and one below. - San Jose scale (Quadraspidiotus perniciosus)
Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow. - White-marked tussock moth (Orygia leucostigma)
Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths.
Locust (Robinia)
- Verticillium wilt (Verticillium )
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 (Verticillium )
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)
- Anthracnose (Several)
Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected. - Cankerworms (Alsophila pometaria)
Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner. Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs. - Cottony maple scale (Pulvinaria innumerabilis)
Flat and pale brown to dark brown, Scales form protruding white egg sacs which are over 1/4th of an inch when the egg mass swells. - Leafhoppers (Several)
3-15 mm in length, wedge shaped with wings that peak over their backs. Nymphs are wingless but active and move readily when disturbed. Adults are winged and fly readily when disturbed. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown. - Maple gall mite (bladder and spindle) (Vasates species)
Adult eeriophid mites are not visible without the aid of a dissecting scope. Mites are 0.05 - 0.2 mm in length and spindle shaped with 4 anterior legs. - Oystershell scale (Lepidosaphes ulmi)
Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax. - Verticillium wilt (Verticillium )
The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash. - White-marked tussock moth (Orygia leucostigma)
Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths. - Yellow-necked caterpillar (Datana ministra)
Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.
Mountain Ash (Sorbus)
- Cedar-rosaceous Rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance. - Lace bugs (Tingidae species)
Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back. - San Jose scale (Quadraspidiotus perniciosus)
Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow.
Oak (Quercus)
- Anthracnose (Several)
Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected. - Cankerworms (Alsophila pometaria)
Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner. Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs. - Fall webworm (Hyphantria cunea)
Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots. - Lace bugs (Tingidae species)
Flat insects approximately 3 mm long, white to light brown or brown with black markings. Wings have a lace like appearance and lay flat over the back. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown. - Oak leaf gall (Several)
Several different wasp species cause galls on oak leaves. - Oak leaf skeletonizer (Bucculatrix ainsliella)
Larvae are pale yellow, sometimes tinted with green and approximately 7mm long. If larvae are disturbed they may spin long silken threads and hang from branches. White webs or cocoons may also be present. - Oak leafminer (Cameraria species)
Several species cause mines in oak leaves. - Oak wilt (Ceratocystis fagacearum)
Initially, single branches on infected trees wilt and die. Leaves on these branches often bronze, or turn tan or dull green, starting at the tips or outer margins. Leaves may also droop, curl, or fall from the tree. Infected trees eventually die. Oak wilt can kill oaks in the red oak group in less than one month. Oaks in the white oak group usually have less severe symptoms and are rarely killed in one season. - Twolined chestnut borer (Agrilus bilineatus)
Borers are 6-12 mm long, greenish black, with fine golden yellow hairs and a pale stripe on each wing cover. Larvae are up to 25 mm long, slender, legless and cream in color. - Yellow-necked caterpillar (Datana ministra)
Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.
Pear (Pyrus)
- Fire blight (Erwinia amylovora)
Blossoms, leaves, twigs, and branches of plants affected by fire blight can turn dark brown to black, giving the appearance of having been scorched in a fire. The blighted blossoms and leaves tend to stay on the tree instead of falling. Current year’s twigs often wilt and bend approximately 180°, forming a “shepherd’s crook.” Cankers develop on branches and stems, and emit a sticky bacterial ooze. Sapwood around cankers may discolor to a reddish brown.
Plum / Cherry (Prunus)
- Bacterial leaf spot & twig blight (Pseudomonas syringae pv. Syringae)
Initial symptoms of bacterial blight may include dark brown necrotic (dead) leaf spots with yellow margins. If leaf spots develop before leaves are fully expanded, leaf curling and twisting may result. More advanced symptoms include necrotic blotches starting at the leaf margins and advancing inward, as well as black streaking on twigs. In its' most severe form, bacterial blight can result in the death of branch tips, leaves and blossoms. - Black knot (Apiosporina morbosa)
During the first year of infection, black knot-infected trees develop greenish-brown to brown swellings on affected branches and trunks. During the second year, these swellings enlarge into the ugly, black, erupting tumors (galls) characteristic of the disease. Older gall tissue (greater than two years old) often dies and then is colonized by fungi that give the gall a whitish or pinkish color. Severe black knot infections may cause general tree decline or death if galls girdle large limbs or tree trunks. - Cankerworms (Alsophila pometaria)
Mature larvae are 20-30 mm in length and vary in color from light green to brownish green to black with one or more stripes of white, green or black. Larvae move in a looping manner. Spring cankerworms have 2 pairs of prolegs and fall cankerworms have 3 pairs of prolegs. - Eastern tent caterpillar (Malacosoma americanum)
Larvae grow to greater than 25 mm in length. Caterpillars have black heads with a white stripe down the length of the back and a yellow stripe on each side with blue markings. - Fall webworm (Hyphantria cunea)
Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown. - Oystershell scale (Lepidosaphes ulmi)
Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax. - Peachtree borer (Synanthedon exitiosa)
Larvae are creamy white with a reddish brown head. - San Jose scale (Quadraspidiotus perniciosus)
Nymphs are circular and dirty white in color. Later stages become gray-brown and develop a yellow center. Coverings on males are similar and elongated. The female's body is yellow. - Verticillium wilt (Verticillium )
The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash. - Yellow-necked caterpillar (Datana ministra)
Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.
Poplar (Populus)
- Anthracnose (Several)
Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected. - Fall webworm (Hyphantria cunea)
Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots.
Redbud (Cercis)
- Verticillium wilt (Verticillium )
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 (Verticillium )
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)
- Cedar-rosaceous Rusts (Cedar-apple, cedar-hawthorn, cedar-quince rust on deciduous hosts) (Gymnosporangium (Deciduous))
On junipers, the cedar-rosaceous rust fungus causes formation of irregularly-shaped brown galls (roughly 1/2 to two inches in diameter). During moist periods in spring, these galls produce a distinctive orange, gelatinous slime. Symptoms on rosaceous hosts appear in late May as circular, yellow-orange areas on leaves. The undersurfaces of these diseased areas often have a fringed appearance. - Verticillium wilt (Verticillium )
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.
Sycamore (Platanus)
- Anthracnose (Several)
Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected.
Tuliptree (Liriodendron )
- Verticillium wilt (Verticillium )
The first signs of Verticillium wilt that you may notice are individual branches that suddenly wilt and die. Affected branches may occur on one side of the tree or may be scattered throughout the tree. If you carefully peel away the bark of these branches, you may see brown or green streaking in the sapwood. Streaking is common in trees such as maple or redbud, but often is not visible in ash.
Walnut (Juglans)
- Anthracnose (Several)
Symptoms of anthracnose vary from host to host, but in general, include irregular spots, and dead areas in leaves that often follow the veins of the leaves. Affected tissue can vary in color, but is often tan or brown. Severely affected leaves often curl and may fall off. In some tree species, such as sycamore, twigs can also become infected. - Fall webworm (Hyphantria cunea)
Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots. - Oystershell scale (Lepidosaphes ulmi)
Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax. - Walnut caterpillar (Datana integerrina)
Larvae are 50 mm long when mature and gray to black with long hairs. Younger larvae are reddish brown with light yellow stripes down the length of their bodies. Adults are stout bodied moths. - White-marked tussock moth (Orygia leucostigma)
Larvae are up to 31 mm long with a reddish orange head and a cream colored body with distinct whitish yellow tufted hairs on the front and hind ends. Adults are moths. - Yellow-necked caterpillar (Datana ministra)
Mature larvae are black except for a yellow orange neck and several yellow lines along the length of the body.
Willow (Salix)
- Fall webworm (Hyphantria cunea)
Larvae are hairy caterpillars are variable in color with paired spots on each segment of the back. The head is red to black. Adults are white moths 18mm long, some having black spots. - Imported willow leaf beetle (Plagiodera versicolor)
Larvae are up to 6 mm in length, black to dark bluish green with rows of tubercles along the body. Adults are 4-5 mm long, greenish blue and oval in shape. - Lecanium scale (Parthenolecanium species)
Family comprised of more than a dozen species of soft scales that are difficult to distinguish from one another but this group has no waxy covering, and lengths of 3-12 mm. Once females lay their eggs her hemispherical body dries and become brown. - Oystershell scale (Lepidosaphes ulmi)
Adult females are oystershell shaped. 3 mm long and light to dark brown. On some hosts the scale is covered with a fine powder of wax. - Spiny elm caterpillar (Nymphalis antiopa)
Dark colored caterpillar with purple markings. Adult is the Morning Cloak Butterfly.