Compiled by Brian Hudelson and Hulubanche Kassa
The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from May 23, 2026 through May 29, 2026.
Broad-Leafed Woody Ornamentals
Plant: Boxwood
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Milwaukee
Plant: Boxwood
Disease/Disorder: Fusarium Canker
Pathogen: Fusarium sp.
Counties: Dane, Waukesha
Plant: Boxwood
Disease/Disorder: Volutella Canker
Pathogen: Volutella sp.
Counties: Dane, Milwaukee, Waukesha
Plant: Ironwood
Disease/Disorder: Leaf Blister (Suspected)
Pathogen: Taphrina virginica
County: Milwaukee
Plant: Lilac
Disease/Disorder: Bacterial Blight
Pathogen: Pseudomonas syringae pv. syringae
County: Dane
Plant: Maple (Norway)
Disease/Disorder: Root/Crown Rot
Pathogens: Phytophthora sp., Cylindrocarpon sp.
County: Racine
Plant: Maple (Red)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
County: Green
Plant: Maple (Red)
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Green
Plant: Maple (Red)
Disease/Disorder: Root/Crown Rot
Pathogen: Phytophthora sp.
County: Waukesha
Plant: Maple (Red)
Disease/Disorder: Verticillium Wilt
Pathogen: Verticillium sp.
County: Waukesha
Plant: Oak (Unspecified)
Disease/Disorder: Herbicide Damage
Pathogens: None
County: Monroe
Field Crops
No New Diseases
Forage Crops
No New Diseases
Fruit Crops
Plant: Apple
Disease/Disorder: Botryosphaeria Canker
Pathogen: Botryosphaeria sp.
County: Dane
Plant: Apple
Disease/Disorder: Cytospora Canker
Pathogen: Cytospora sp.
County: Waupaca
Plant: Apple
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Dane
Plant: Apple
Disease/Disorder: Phomopsis Canker
Pathogen: Phomopsis sp.
County: Dane
Herbaceous Ornamentals
Plant: Peony
Disease/Disorder: Xanthomonas Blight
Pathogens: Xanthomonas sp.
County: Dane
Houseplants
No New Diseases
Needled Woody Ornamentals
Plant: Arborvitae
Disease/Disorder: Winter Burn (Suspected)
Pathogens: None
County: Waukesha
Plant: Fir (Unspecified)
Disease/Disorder: Gelatinosporium Canker
Pathogen: Gelatinosporium sp.
County: Dane
Plant: Spruce (Unspecified)
Disease/Disorder: Root/Crown Rot
Pathogen: Pythium sp.
County: La Crosse
Vegetable Crops
Plant: Potato
Disease/Disorder: Black Leg
Pathogens: Dickeya dianthicola, Pectobacterium sp.
County: Waushara
Specialty Crops
No New Diseases
Miscellaneous
No New Entries