Compiled by Brian Hudelson and Hulubanche Kassa
The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from May 16, 2026 through May 22, 2026.
Broad-Leafed Woody Ornamentals
Plant: Boxwood
Disease/Disorder: Fusarium Canker
Pathogen: Fusarium sp.
Counties: Green, Waukesha
Plant: Boxwood
Disease/Disorder: Genetic Sport
Pathogen: None
County: Green
Plant: Boxwood
Disease/Disorder: Volutella Canker
Pathogen: Volutella sp.
Counties: Green, Waukesha
Plant: Boxwood
Disease/Disorder: Winter Burn
Pathogen: None
County: Green
Plant: Cherry (Unspecified)
Disease/Disorder: Black Knot
Pathogen: Apiosporina morbosa
County: Dane
Plant: Crabapple
Disease/Disorder: Apple Scab
Pathogen: Venturia inaequalis
County: Walworth
Plant: Holly
Disease/Disorder: Phoma Leaf Spot
Pathogen: Phoma sp.
County: Dane
Plant: Holly
Disease/Disorder: Septoria Leaf Spot
Pathogen: Septoria sp.
County: Dane
Plant: Lilac
Disease/Disorder: Anthracnose
Pathogen: Gloeosporium sp.
County: Dane
Plant: Lilac
Disease/Disorder: Root/Crown Rot
Pathogens: Fusarium sp., Rhizoctonia sp.
County: Dane
Plant: Lilac
Disease/Disorder: Septoria Leaf Spot/Blight
Pathogens: Septoria sp.
County: Waukesha
Plant: Ninebark
Disease/Disorder: Powdery Mildew
Pathogen: Oidium sp.
Counties: Dane, Waukesha
Plant: Pear (Callery)
Disease/Disorder: Tubercularia/Nectria Canker
Pathogens: Tubercularia sp./Nectria sp.
County: Dunn
Field Crops
No New Diseases
Forage Crops
No New Diseases
Fruit Crops
Plant: Apple
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Jefferson
Plant: Apple
Disease/Disorder: Cytospora Canker
Pathogen: Cytospora sp.
County: Waupaca
Plant: Aronia
Disease/Disorder: Transplant Shock (Suspected)
Pathogen: None
County: Dane
Plant: Cherry
Disease/Disorder: Bacterial Canker
Pathogen: Pseudomonas syringae
County: Dane
Herbaceous Ornamentals
Plant: Astilbe
Disease/Disorder: Tobacco Rattle
Pathogens: Tobacco rattle virus
County: Jefferson
Plant: Bleeding Heart
Disease/Disorder: Tobacco Rattle
Pathogens: Tobacco rattle virus
County: Jefferson
Plant: Hosta
Disease/Disorder: Storm Damage (Suspected)
Pathogens: None
County: Brown
Plant: Pachysandra
Disease/Disorder: Volutella Blight
Pathogens: Volutella pachysandricola
County: Dane
Plant: Peony
Disease/Disorder: Septoria Leaf Spot
Pathogens: Septoria sp.
County: Dane
Houseplants
No New Diseases
Needled Woody Ornamentals
Plant: Pine (White)
Disease/Disorder: Transplant Shock (Suspected)
Pathogens: None
County: Dane
Plant: Spruce (Black Hills)
Disease/Disorder: Rhizosphaera Needle Cast
Pathogen: Rhizosphaera kalkhoffii
County: St. Croix
Plant: Spruce (Blue)
Disease/Disorder: Rhizosphaera Needle Cast
Pathogen: Rhizosphaera kalkhoffii
County: Waukesha
Plant: Spruce (Unspecified)
Disease/Disorder: Rhizosphaera Needle Cast
Pathogen: Rhizosphaera kalkhoffii
County: Dodge
Vegetable Crops
No New Diseases
Specialty Crops
No New Diseases
Miscellaneous
No New Entries