Compiled by Brian Hudelson and Dante Tauscheck
The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from June 14, 2025 through June 20, 2025.
Broad-Leafed Woody Ornamentals
Plant: Boxwood
Disease/Disorder: Volutella Canker
Pathogen: Volutella sp.
County: Dane
Plant: Buckthorn (Fern Leaf)
Disease/Disorder: Crown Rust
Pathogen: Puccinia coronata
County: Dane
Plant: Burning Bush
Disease/Disorder: Herbicide Damage
Pathogen: None
County: Dane
Plant: Cherry (Sand)
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Dane
Plant: Crabapple
Disease/Disorder: Apple Scab
Pathogen: Venturia inaequalis
Counties: Dane, Racine
Plant: Crabapple
Disease/Disorder: Chlorosis
Pathogen: None
County: Dane
Plant: Crabapple
Disease/Disorder: Phomopsis Canker
Pathogen: Phomopsis sp.
County: Dane
Plant: Elm (Unspecified)
Disease/Disorder: Dutch Elm Disease
Pathogen: Ophiostoma sp.
County: La Crosse
Plant: Magnolia
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Dane
Plant: Maple (Sugar)
Disease/Disorder: Squirrel Damage
Pathogen: None
County: Washington
Plant: Maple (Unspecified)
Disease/Disorder: Root/Crown Rot
Pathogens: Pythium sp., Fusarium sp.
County: Waukesha
Plant: Oak (Red)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
County: Waukesha
Plant: Oak (Red)
Disease/Disorder: Oak Wilt
Pathogen: Bretziella fagacearum
County: Columbia
Plant: Oak (White)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
County: Lake (IL)
Plant: Oak (White)
Disease/Disorder: Chlorosis
Pathogen: None
County: Lake (IL)
Plant: Oak (White)
Disease/Disorder: Tubakia Leaf Spot
Pathogen: Tubakia dryina
County: Lake (IL)
Plant: Redbud
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Dane
Field Crops
No New Diseases
Forage Crops
No New Diseases
Fruit Crops
Plant: Plum
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Portage
Herbaceous Ornamentals
Plant: Hosta
Disease/Disorder: Host Virus X (Suspected)
Pathogen: Hosta virus X
County: Milwaukee
Plant: Monarda
Disease/Disorder: Chemical Burn (Suspected)
Pathogen: None
County: Sawyer
Plant: Pachysandra
Disease/Disorder: Volutella Blight
Pathogen: Volutella pachysandricola
County: Milwaukee
Plant: Peony
Disease/Disorder: Root/Crown Rot
Pathogens: Phytophthora sp., Rhizoctonia sp.
County: Iowa
Plant: Phlox
Disease/Disorder: Chemical Burn (Suspected)
Pathogen: None
County: Sawyer
Plant: St. John’s-Wort
Disease/Disorder: Rust
Pathogen: Melampsora hypericorum (Suspected)
County: La Crosse
Plant: Veronica
Disease/Disorder: Chemical Burn (Suspected)
Pathogen: None
County: Sawyer
Houseplants
No New Diseases
Needled Woody Ornamentals
Plant: Arborvitae
Disease/Disorder: Winter Burn (Suspected)
Pathogen: None
County: Waukesha
Plant: Fir (White)
Disease/Disorder: Phyllosticta Needle Blight
Pathogen: Phyllosticta sp.
County: Dane
Plant: Juniper
Disease/Disorder: Cedar-Quince Rust
Pathogen: Gymnosporangium clavipes
County: Dane
Plant: Juniper
Disease/Disorder: Cytospora Canker
Pathogen: Cytospora sp.
County: Waukesha
Plant: Juniper
Disease/Disorder: Phomopsis Tip Blight
Pathogen: Phomopsis juniperovora
County: Dane
Plant: Juniper
Disease/Disorder: Stigmina Needle Blight
Pathogen: Stigmina juniperina
County: Waukesha
Plant: Juniper
Disease/Disorder: Winter Burn
Pathogen: None
County: Waukesha
Plant: Yew
Disease/Disorder: Phomopsis Canker
Pathogen: Phomopsis sp.
County: Waukesha
Vegetable Crops
Plant: Onion
Disease/Disorder: Root Rot
Pathogen: Pythium sp.
County: Dodge
Plant: Pea
Disease/Disorder: Root Rot
Pathogens: Aphanomyces euteiches, Fusarium sp., Pythium sp., Rhizoctonia sp.
County: Waushara
Specialty Crops
No New Diseases
Miscellaneous
Mushroom ID: Dead Man’s Fingers (Xylaria polymorpha)
County: Winnebago
Mushroom ID: Varnish Shelf (Ganoderma sp.)
County: Winnebago
Mushroom ID: Glistening Inky Cap (Coprinellus micaceus)
County: Waukesha
Mushroom ID: Woodland Inkcap (Coprinellus deliquescens)
County: Waukesha