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Plant: Amsonia (Amsonia sp.) (Apocynaceae) Back to List Disease/Disorder: Leaf rust Causal agent:Coleosporium sp.(fungus) Signs: rust pustules with urediniospores on leaf surface Symptoms: rust pustules on leaf surface. Total image number: 6
Plant: Azalea (Rhododendron sp.) (Ericaceae) Back to List Disease/Disorder: Leaf and flower gall Causal agent:Exobasidium vaccinii (fungus) Signs: gall is fungal tissue Symptoms: Leaf becomes galled tissue. Total image number: 4
Plant: Birch (Betula sp.) (Betulaceae) Back to List Disease/Disorder: Leaf spot Causal agent:Septoria betulae (fungus) Signs: raised spore-producing bodies ("pycnidia") can be seen within spots. Symptoms: Leaf spots can coalesce to form blighted areas. Total image number: 4
Plant: Birch (Betula sp.) (Betulaceae) Back to List Disease/Disorder: Leaf spot Causal agent:Cryptocline betularum (fungus) Signs: spore-producing bodies ("acervuli") can be seen within spots Symptoms: Tan to gray spots on leaves. Total image number: 6
Plant: Boxwood (Buxus sp.) (Buxaceae) Back to List Disease/Disorder: Pseudonectria canker/Volutella leaf and stem blight Causal agent:Pseudonectria rousseliana (imperfect state - Volutella buxi (fungus) Signs: pink to salmon to orange spore-producing bodies ("acervuli") can be seen covering stems and leaves. Dark pink to red sterile hyphae ("setae") can also be seen. Symptoms: Dieback of stems with leaves turning tan brown. Total image number: 12
Plant: Cherry (Prunus sp.) (Rosaseae) Back to List Disease/Disorder: Leaf spot Causal agent:Phloeosporella padi (fungus) Signs: Spore-producing bodies ("acervuli") may be swelled like a blister, sometimes not. Symptoms: dark brown leaf spots with red border Total image number: 8
Plant: Cherry (Prunus sp.) (Rosaseae) Back to List Disease/Disorder: Rust Causal agent:Tranzschelia sp. (fungus) Signs: Pustules with spores ("urediniospores") [found on same leaf as with Phloeosporella padi above] Symptoms: raised spots surrounded by light green/white leaf tissue Total image number: 5
Plant: Cherry (Prunus sp.) (Rosaseae) Back to List Disease/Disorder: Leaf spot Causal agent:Cercospora sp. (fungus) Signs: Spore-producing hyphae ("conidiophores") grouped in clumps. Symptoms: reddish-brown spots which can drop out and form shot-holes. Total image number: 8
Plant: Clematis (Clematis sp.) (Ranunculaceae) Back to List Disease/Disorder: Leaf spot/blotch Causal agent:Phoma or Ascochyta (fungus) Signs: reddish-brown spore-producing bodies ("pycnidia") not well defined within spot/blotches. Symptoms: brown to reddish-brown spots/blotches Total image number: 7
Plant: Dogwood (Cornus florida) (Cornaceae) Back to List Disease/Disorder: Septoria leaf spot Causal agent:Septoria cornicola (fungus) Signs: raised spore-producing bodies ("pycnidia") can be seen within spots. Symptoms: darkened leaf spots Total image number: 4
Plant: Elm (Ulmus carpinifolia 'Accolade') (Ulmaceae) Back to List Disease/Disorder: Leaf spot Causal agent:unknown (fungus) possibly Phyllosticta Signs: spore-producing bodies ("pycnidia") can be seen within spots Symptoms: Tan to gray spots on leaves. Total image number: 4
Plant: Elm (Ulmus sp.) (Ulmaceae) Back to List Disease/Disorder: Black spot Causal agent:Stegophora ulmea (fungus) Signs: raised spore-producing bodies ("acervulus") can be seen within spots. Symptoms: small, raised black spots with a fine area of white tissue surrounding them, found mostly between the major veins of the leaves Total image number: 4
Plant: Elm (Ulmus sp.) (Ulmaceae) Back to List Disease/Disorder: Dutch elm disease (DED) Causal agent:Ophiostoma ulmi(fungus) Signs: Incubation of symptomatic pieces of elm branches, surface sterilized and placed in an incubation chamber produced the characteristic asexual stage or "synnemata" (conidiophores with clusters of colorless conidia) of the fungus. Symptoms: Tree limbs will dieback and eventually the entire tree will die Total image number: 9
Each of the last two rows of images is of a different sample.
Plant: Forsythia (Forsythia sp.) (Oleaceae) Back to List Disease/Disorder: Twig dieback Causal agent:Sclerotinia sp. (fungus) Signs: hard, black survival structure called a “sclerotia” inside the stem Symptoms: starts as a flower infection and work its way into the stem. On the stems, notice at the margin between healthy and diseased tissue you will see a copper/brown area on the stem. Within this area you can see a pattern of alternating lighter and darker copper/brown lines. Total image number: 4
Plant: Forsythia (Forsythia sp.) (Oleaceae) Back to List Disease/Disorder: Galls Causal agent: attributed to Phomopsis sp. (fungus) Signs: small, black pycnidia randomly occurring in gall tissue Symptoms: Galls are nodular, each with multiple centers of growth and are usually associated with twig dieback. Total image number: 12
Plant: Apple, but can occur on Crabapple (Malus sp.) (Rosaceae) Back to List Disease/Disorder: Fire blight. Causal agent:Erwinia amylovora (bacterium) Signs: May see droplets or oozings of bacteria from blighted tissue. Bacterial streaming from infected tissue. Symptoms: Blighted shoot tips and/or flower blossom spurs. Total image number: 4
Plant: Apple, but can occur on Crabapple (Malus sp.) (Rosaceae) Back to List Disease/Disorder: Vole injury Causal agent:Microtus spp. (rodent) Signs: Symptoms: vole (rodent) injury on larger roots of orchard tree. Total image number: 4
Plant: Apple, but can occur on Crabapple (Malus sp.) (Rosaceae) Back to List Disease/Disorder: Cedar/Apple rust Causal agent:Gymnosprangium juniperi-virginianae (fungus) Signs: aecia forming on leaves and releasing spores (aeciospores) from bottom of leaf. Symptoms: The spots on the top surface of the leaves are due to spores coming from cedar trees - the fungal stage at the bottom surface of the leaf opposite the same spot is the stage which produces spores which infect cedar trees. Total image number: 4
Plant: Holly, Blue (Ilex x meserveae) (Aquafoliaceae) Back to List
Disease/Disorder: web blight Causal agent:Rhizoctonia sp. (fungus) Signs: white to tan mycelium seen branches and leaves. Symptoms: Death of leaves. We attributed this outbreak to the long moist period associated with Hurricane Katrina. Total image number: 4
Plant: Honeylocust (Gleditsia triacanthos var. inermis 'Skyline') (Fabaceae) Back to List Disease/Disorder: Leaf spot Causal agent:Cercospora sp. (fungus) Signs: Spore-producing hyphae ("conidiophores") grouped in clumps. Symptoms: brown spots with lighter center and darker brown boarder Total image number: 7
Plant: Kerria, Japanese (Kerria japonica) (Rosaceae) Back to List
Disease/Disorder: Leaf/twig blight Causal agent:Blumeriella kerriae (teleomorph). Anamorph (Phloeosporella) seen in images below. Signs: a ring of raised, spore-producing bodies ("acervuli") within spot. Symptoms: On the leaves infection shows as reddish spots with dark borders and, if numerous, leaves yellow and fall. Stem cankers are produced as discolored more or less extended darkened areas which may crack open. Total image number: 4
Plant: Leucothoe, drooping (Leucothoe fontanesiana) (Ericaceae) Back to List
Disease/Disorder: Leaf spot Causal agent:Phyllosticta sp. Signs: black, spore-producing bodies ("conidia") within spot. Symptoms: Brown spots with a darker color border. A bull's eye pattern can be seen in the larger spots. Total image number: 9
Plant: Maple, 'Autumn Blaze' (Acer rubrum 'Autumn Blaze') (Aceraceae) Back to List Disease/Disorder: Verticillium wilt Causal agent:Verticillium spp. (fungus) Signs: Symptoms: Nursery trees shortly after transplanting showed poor growth. Sample of a darkened section of the vascular tissue of the stem below ground plated on a culture medium. After several days the fungal growth showed characteristic spore-producing structures for the fungus, Verticillium, species unknown. Total image number: 9
Plant: Maple, silver (Acer saccharinum) (Aceraceae) Back to List
Disease/Disorder: Anthracnose Causal agent:Monostichella sp. (fungus). Signs: a ring of slightly raised, spore-producing bodies ("acervuli") within spot. Symptoms: brown spots on leaves. Total image number: 4
Plant: Maple, 'Autumn Blaze' (Acer rubrum 'Autumn Blaze') (Aceraceae) Back to List Disease/Disorder: Anthracnose/Leaf blight ? Causal agent:Discula sp.? (fungus) Signs: off-white to tan spore-producing bodies ("acervuli") seen in clusters on underside of leaf. Symptoms: Large tan brown areas with brown black borders on leaves. Total image number: 12