Compiled by Brian Hudelson and Dante Tauscheck

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from August 2, 2025 through August 8, 2025.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Aspen (Quaking)
Disease/Disorder:  Venturia Leaf and Shoot Blight
Pathogen:  Venturia morelettii
County:  Dane

Plant:  Beech 
Disease/Disorder:  Cold Injury (Suspected)
Pathogen:  None
County:  Ozaukee

Plant:  Beech 
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Ozaukee

Plant:  Boxwood 
Disease/Disorder:  Volutella Canker
Pathogen:  Volutella sp.
County:  Dane

Plant:  Catalpa
Disease/Disorder:  Verticillium Wilt
Pathogen:  Verticillium sp.
County:  Dane

Plant:  Elm (American)
Disease/Disorder:  Dutch Elm Disease
Pathogen:  Ophiostoma sp.
County:  Dane

Plant:  Hydrangea
Disease/Disorder:  Girdling (from attached strings)
Pathogen:  None
County:  Door

Plant:  Hydrangea
Disease/Disorder:  Root Rot
Pathogen:  Phytophthora sp.
County:  Sawyer

Plant:  Lilac
Disease/Disorder:  Root Rot
Pathogen:  Phytophthora sp.
County:  Sawyer

Plant:  Lilac
Disease/Disorder:  Verticillium Wilt (Suspected)
Pathogen:  Verticillium sp.
County:  Dodge

Plant:  Magnolia
Disease/Disorder:  Root Rot
Pathogen:  Rhizoctonia sp.
County:  Dane

Plant:  Maple (Unspecified)
Disease/Disorder:  Anthracnose
Pathogen:  Discula sp.
County:  La Crosse

Plant:  Maple (Unspecified)
Disease/Disorder:  Steganosporium Canker
Pathogen:  Steganosporium sp.
County:  Waukesha

Plant:  Ninebark
Disease/Disorder:  Powdery Mildew
Pathogen:  Oidium sp.
County:  Dane

Plant:  Oak (Swamp White)
Disease/Disorder:  Chlorosis
Pathogen:  None
County:  Dane

Plant:  Oak (White)
Disease/Disorder:  Anthracnose
Pathogen:  Discula sp.
County:  Dane

Plant:  Oak (White)
Disease/Disorder:  Tubakia Leaf Spot
Pathogen:  Tubakia dryina
County:  Dane

Plant:  Oak (White)
Disease/Disorder:  White Rot
Pathogen:  Irpex lacteus
County:  Dane

Plant:  Rose
Disease/Disorder:  Anthracnose
Pathogen:  Gloeosporium sp.
County:  Sawyer

Plant:  Rose
Disease/Disorder:  Gray Mold (Botrytis Blight)
Pathogen:  Botrytis cinerea
County:  Sawyer

Plant:  Rose
Disease/Disorder:  Root Rot
Pathogen:  Phytophthora sp.
County:  Sawyer

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Field Crops

Plant:  Corn (Field)
Disease/Disorder:  Southern Corn Rust
Pathogen:  Puccinia polysora
Counties:  Grant, Green, Green Lake

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Forage Crops

No New Diseases

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Fruit Crops

Plant:  Apple
Disease/Disorder:  Cold Injury (Suspected)
Pathogen:  None
Counties:  Waupaca, Wood

Plant:  Apple
Disease/Disorder:  Root Rot
Pathogen:  Phytophthora sp.
County:  Wood

Plant:  Apple
Disease/Disorder:  Marssonina Leaf Blotch
Pathogen:  Marssonina coronaria
County:  Dunn

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Herbaceous Ornamentals

Plant:  Hosta
Disease/Disorder:  Southern Blight
Pathogen:  Athelia rolfsii
County:  Columbia

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Houseplants

No New Diseases

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Needled Woody Ornamentals

Plant:  Arborvitae
Disease/Disorder:  Cytospora Canker
Pathogen:  Cytospora sp.
County:  Door

Plant:  Arborvitae
Disease/Disorder:  Root Rot
Pathogens:  Phytophthora sp., Pythium sp., Fusarium sp.
Counties:  Dane, Racine

Plant:  Arborvitae
Disease/Disorder:  Sphaeropsis Canker
Pathogen:  Sphaeropsis sp.
County:  Dane

Plant:  Fir (Balsam)
Disease/Disorder:  Cytospora Canker
Pathogen:  Cytospora sp.
County:  Waukesha

Plant:  Juniper
Disease/Disorder:  Winter Burn
Pathogen:  None
County:  Dane

Plant:  Larch (Unspecified)
Disease/Disorder:  Herbicide Damage (Suspected)
Pathogen:  None
County:  Washington

Plant:  Spruce (Bird’s Nest)
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Dane

Plant:  Spruce (Norway)
Disease/Disorder:  Transplant Shock (Suspected)
Pathogen:  None
County:  Waukesha

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Vegetable Crops

Plant:  Cucumber
Disease/Disorder:  Anthracnose
Pathogen:  Colletotrichum orbiculare
County:  Manitowoc

Plant:  Onion
Disease/Disorder:  Stemphylium Leaf Blight
Pathogen:  Stemphylium sp.
County:  Waushara

Plant:  Pepper
Disease/Disorder:  Bacterial Spot
Pathogen:  Xanthomonas sp.
County:  Iowa

Plant:  Potato
Disease/Disorder:  Foliar Blight
Pathogen:  Phytophthora nicotianae
County:  Adams

Plant:  Tomato
Disease/Disorder:  Walnut Toxicity (Suspected)
Pathogen:  None
County:  Dane

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Specialty Crops

No New Diseases

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Miscellaneous

Mushroom ID:  Glistening Inky Cap (Coprinellus micaceus) 
County:  Walworth

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