Compiled by Brian Hudelson and Dante Tauscheck
The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from September 13, 2025 through September 19, 2025.
Broad-Leafed Woody Ornamentals
Plant: Boxwood
Disease/Disorder: Volutella Canker
Pathogen: Volutella sp.
County: Waukesha
Plant: Catalpa
Disease/Disorder: Verticillium Wilt
Pathogen: Verticillium sp.
County: St. Croix
Plant: Hickory (Shagbark)
Disease/Disorder: Root Rot
Pathogen: Pythium sp.
County: Dane
Plant: Lilac (Shrub)
Disease/Disorder: Sphaeropsis Canker
Pathogen: Sphaeropsis sp.
County: Cook (IL)
Plant: Oak (Bur)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
County: Dane
Plant: Oak (Bur)
Disease/Disorder: Monochaetia Leaf Spot
Pathogen: Monochaetia sp.
County: Dane
Plant: Oak (Northern Red)
Disease/Disorder: Oak Wilt
Pathogen: Bretziella fagacearum
County: Marinette
Plant: Oak (Red)
Disease/Disorder: Oak Wilt
Pathogen: Bretziella fagacearum
Counties: Waukesha, Winnebago
Plant: Oak (White)
Disease/Disorder: Chlorosis
Pathogen: None
County: Dane
Plant: Oak (White)
Disease/Disorder: Tubakia Leaf Spot
Pathogen: Tubakia dryina
County: Dane
Plant: Oak (Unspecified)
Disease/Disorder: Chlorosis
Pathogen: None
County: Waukesha
Plant: Oak (Unspecified)
Disease/Disorder: Oak Wilt
Pathogen: Bretziella fagacearum
County: Walworth
Plant: Oak (Unspecified)
Disease/Disorder: Sphaeropsis Canker
Pathogen: Sphaeropsis sp.
County: Racine
Plant: Redbud
Disease/Disorder: Verticillium Wilt
Pathogen: Verticillium sp.
County: Walworth
Plant: Rose
Disease/Disorder: Black Spot
Pathogen: Marssonina rosae
County: Milwaukee
Plant: Sumac (Fragrant)
Disease/Disorder: Root Rot
Pathogen: Cylindrocarpon sp.
County: Dane
Plant: Viburnum
Disease/Disorder: Phomopsis Canker
Pathogen: Phomopsis sp.
County: Kenosha
Plant: Virginia-Creeper
Disease/Disorder: Root Rot
Pathogens: Pythium sp., Rhizoctonia sp.
County: Dane
Field Crops
Plant: Corn (Field)
Disease/Disorder: Gibberella Stalk Rot
Pathogen: Fusarium graminearum
County: Jefferson
Plant: Corn (Field)
Disease/Disorder: Northern Corn Leaf Spot
Pathogen: Bipolaris zeicola
County: Portage
Plant: Soybean
Disease/Disorder: Brown Stem Rot
Pathogen: Phialophora gregata
Counties: Columbia, Dodge
Plant: Soybean
Disease/Disorder: Soybean Cyst Nematode
Pathogen: Heterodera glycines
County: Columbia
Plant: Soybean
Disease/Disorder: Sudden Death Syndrome
Pathogen: Fusarium virguliforme
Counties: Lafayette, Sheboygan
Forage Crops
No New Diseases
Fruit Crops
Plant: Apple
Disease/Disorder: Bitter Pit/Cork Spot
Pathogen: None
County: St. Croix
Plant: Apple
Disease/Disorder: Frogeye Leaf Spot
Pathogen: Botryosphaeria obtusa
County: Portage
Plant: Avocado
Disease/Disorder: Root Rot
Pathogens: Phytophthora sp., Pythium sp., Rhizoctonia sp., Fusarium sp., Cylindrocarpon sp.
County: Walworth
Plant: Cranberry
Disease/Disorder: Blotch Rot
Pathogen: Physalospora vaccinii
County: Monroe
Plant: Cranberry
Disease/Disorder: Early Rot
Pathogen: Phyllosticta vaccinii
County: Monroe
Plant: Cranberry
Disease/Disorder: Viscid Rot
Pathogen: Phomopsis sp.
County: Jackson
Plant: Pear
Disease/Disorder: Pear Scab
Pathogen: Venturia pirina
County: Vernon
Herbaceous Ornamentals
Plant: Phlox
Disease/Disorder: Root Rot
Pathogen: Phytophthora sp.
County: Jefferson
Houseplants
No New Diseases
Needled Woody Ornamentals
Plant: Arborvitae
Disease/Disorder: Improper Planting
Pathogen: None
County: St. Croix
Plant: Arborvitae
Disease/Disorder: Transplant Shock (Suspected)
Pathogen: None
County: St. Croix
Plant: Arborvitae
Disease/Disorder: Water Stress
Pathogen: None
County: St. Croix
Plant: Juniper
Disease/Disorder: Root Rot
Pathogen: Pythium sp.
County: Milwaukee
Plant: Pine (Swiss Stone)
Disease/Disorder: Root Rot
Pathogen: Pythium sp.
County: Milwaukee
Plant: Spruce (Dwarf)
Disease/Disorder: Winter Burn/Injury
Pathogen: None
County: Dane
Vegetable Crops
No New Diseases
Specialty Crops
No New Diseases
Miscellaneous
Plant: Grass (Unspecified)
Disease/Disorder: Rust
Pathogen: Puccinia sp.
County: Lafayette
Plant: Grass (Unspecified)
Disease/Disorder: Tar Spot
Pathogen: Phyllachora sp.
County: Lafayette