Compiled by Brian Hudelson and Dante Tauscheck
The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from August 9, 2025 through August 15, 2025.
Broad-Leafed Woody Ornamentals
Plant: Aspen
Disease/Disorder: Marssonina Leaf Spot and Blight
Pathogen: Marssonina sp.
County: Dane
Plant: Cherry (Black)
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Dane
Plant: Crabapple
Disease/Disorder: Sphaeropsis Canker
Pathogen: Sphaeropsis sp.
County: Dane
Plant: Lilac (Unspecified)
Disease/Disorder: Verticillium Wilt
Pathogen: Verticillium sp.
County: Waukesha
Plant: Maple (Unspecified)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
County: Jefferson
Plant: Maple (Unspecified)
Disease/Disorder: Melanconis Canker
Pathogen: Melanconis sp.
County: Dane
Plant: Maple (Unspecified)
Disease/Disorder: Sunburn
Pathogen: None
County: Jefferson
Plant: Ninebark
Disease/Disorder: Anthracnose
Pathogen: Colletotrichum sp.
County: Crawford
Plant: Ninebark
Disease/Disorder: Cercospora Leaf Spot
Pathogen: Cercospora sp.
County: Crawford
Plant: Oak (Bur)
Disease/Disorder: Oak Wilt
Pathogen: Bretziella fagacearum
County: Dane
Plant: Oak (White)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
Counties: Dane, Lake (IL)
Plant: Oak (White)
Disease/Disorder: Chlorosis
Pathogen: None
Counties: Dane, Lake (IL)
Plant: Oak (White)
Disease/Disorder: Monochaetia Leaf Spot
Pathogen: Monochaetia sp.
County: Lake (IL)
Plant: Oak (White)
Disease/Disorder: Tubakia Leaf Spot
Pathogen: Tubakia dryina
Counties: Dane, Lake (IL)
Plant: Oak (Unspecified)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
County: Winnebago
Plant: Oak (Unspecified)
Disease/Disorder: Chlorosis
Pathogen: None
County: Winnebago
Plant: Oak (Unspecified)
Disease/Disorder: Monochaetia Leaf Spot
Pathogen: Monochaetia sp.
County: Winnebago
Plant: Oak (Unspecified)
Disease/Disorder: Oak Wilt
Pathogen: Bretziella fagacearum
Counties: Dane, Marathon
Plant: Oak (Unspecified)
Disease/Disorder: Smooth Patch
Pathogen: None
County: Dane
Plant: Oak (Unspecified)
Disease/Disorder: Tubakia Leaf Spot
Pathogen: Tubakia dryina
County: Winnebago
Plant: Ohio Buckeye
Disease/Disorder: Edema
Pathogen: None
County: Dane
Plant: Redbud
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Dane
Plant: Sumac (Fragrant)
Disease/Disorder: Fusarium Wilt
Pathogen: Fusarium sp.
County: Waukesha
Field Crops
Plant: Corn (Field)
Disease/Disorder: Southern Corn Rust
Pathogen: Puccinia polysora
Counties: Brown, Outagamie
Plant: Wheat
Disease/Disorder: Head Weathering
Pathogen: Miscellaneous fungi
County: Sheboygan
Forage Crops
Plant: Alfalfa
Disease/Disorder: Bacterial Wilt
Pathogen: Clavibacter michiganensis subsp. insidiosus
County: Manitowoc
Plant: Alfalfa
Disease/Disorder: Root Rot
Pathogen: Rhizoctonia sp., Fusarium sp.
County: Manitowoc
Fruit Crops
Plant: Blueberry
Disease/Disorder: Chlorosis
Pathogen: None
County: St. Croix
Plant: Blueberry
Disease/Disorder: Phomopsis Canker
Pathogen: Phomopsis sp.
County: St. Croix
Plant: Blueberry
Disease/Disorder: Transplant Shock (Suspected)
Pathogen: None
County: Dane
Plant: Grape
Disease/Disorder: Black Rot
Pathogen: Phyllosticta ampelicida
County: Dane
Plant: Plum
Disease/Disorder: Black Knot
Pathogen: Apiosporina morbosa
County: Iowa
Plant: Strawberry
Disease/Disorder: Root/Crown Rot
Pathogens: Phytophthora sp., Rhizoctonia sp.
County: St. Croix
Herbaceous Ornamentals
Plant: Coral Bells
Disease/Disorder: Anthracnose
Pathogen: Colletotrichum sp.
County: Boone (IL)
Plant: Hibiscus
Disease/Disorder: Herbicide Damage
Pathogen: None
County: Boone (IL)
Plant: Veronica
Disease/Disorder: Septoria Leaf Spot
Pathogen: Septoria sp.
County: Winnebago
Plant: Zinnia
Disease/Disorder: Bacterial Leaf Spot
Pathogen: Xanthomonas campestris pv. zinniae
County: Bayfield
Houseplants
No New Diseases
Needled Woody Ornamentals
Plant: Juniper
Disease/Disorder: Diplodia Shoot Blight and Canker
Pathogen: Diplodia sp.
County: Waukesha
Plant: Juniper
Disease/Disorder: Winter Burn
Pathogen: None
County: Jefferson
Vegetable Crops
Plant: Asparagus
Disease/Disorder: Phomopsis Canker
Pathogen: Phomopsis sp.
County: Waushara
Plant: Asparagus
Disease/Disorder: Root Rot
Pathogen: Fusarium sp.
County: Waushara
Plant: Cucumber
Disease/Disorder: Alternaria Leaf Spot
Pathogen: Alternaria sp.
County: Adams
Plant: Cucumber
Disease/Disorder: Anthracnose
Pathogen: Colletotrichum orbiculare
County: Adams
Plant: Snap Bean
Disease/Disorder: Root Rot
Pathogens: Aphanomyces sp., Fusarium sp.
County: Oconto
Plant: Snap Bean
Disease/Disorder: Halo Blight
Pathogen: Pseudomonas savastanoi pv. phaseolicola
County: Manitowoc
Specialty Crops
No New Diseases
Miscellaneous
No New Entries