Compiled by Brian Hudelson and Dante Tauscheck
The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from August 23, 2025 through August 29, 2025.
Broad-Leafed Woody Ornamentals
Plant: Buckeye (Bottlebrush)
Disease/Disorder: Guignardia Leaf Blotch
Pathogen: Guignardia aesculi
County: Columbia
Plant: Catalpa
Disease/Disorder: Verticillium Wilt
Pathogen: Verticillium sp.
County: Sheboygan
Plant: Cherry (Black)
Disease/Disorder: Root Rot
Pathogen: Phytophthora sp., Rhizoctonia sp.
County: Dane
Plant: Crabapple
Disease/Disorder: Chlorosis
Pathogen: None
County: Green
Plant: Elm (American)
Disease/Disorder: Blackspot
Pathogen: Asteroma ulmeum
County: Waukesha
Plant: Lilac
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Dane
Plant: Magnolia
Disease/Disorder: Verticillium Wilt
Pathogen: Verticillium sp.
County: Dane
Plant: Maple
Disease/Disorder: Girdling Roots (Suspected)
Pathogen: None
County: La Crosse
Plant: Maple
Disease/Disorder: Overly Deep Planting
Pathogen: None
County: La Crosse
Plant: Oak (Bur)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
County: Dane
Plant: Oak (Bur)
Disease/Disorder: Tubakia Leaf Spot
Pathogen: Tubakia dryina
County: Dane
Plant: Oak (Pin)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
County: Dane
Plant: Oak (Pin)
Disease/Disorder: Chlorosis
Pathogen: None
County: Dane
Plant: Oak (Pin)
Disease/Disorder: Tubakia Leaf Spot
Pathogen: Tubakia dryina
County: Dane
Plant: Oak (Red)
Disease/Disorder: Oak Wilt
Pathogen: Bretziella fagacearum
County: Cook (IL)
Plant: Oak (White)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
County: Dane
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: Oak Wilt
Pathogen: Bretziella fagacearum
County: Dane
Plant: Pear (Callery/Ornamental)
Disease/Disorder: Fire Blight
Pathogen: Erwinia amylovora
Counties: Dane, Waukesha
Field Crops
Plant: Corn (Field)
Disease/Disorder: Southern Corn Rust
Pathogen: Puccinia polysora
County: Lafayette
Plant: Corn (Field)
Disease/Disorder: Tar Spot
Pathogen: Phyllachora maydis
County: Lafayette
Plant: Soybean
Disease/Disorder: Soybean Cyst Nematode
Pathogen: Heterodera glycines
County: Sheboygan
Plant: Soybean
Disease/Disorder: Sudden Death Syndrome
Pathogen: Fusarium virguliforme
Counties: Lafayette, Sheboygan
Forage Crops
No New Diseases
Fruit Crops
Plant: Apple (‘Honeycrisp’)
Disease/Disorder: Honeycrisp Leaf Mottle
Pathogen: None
County: Wood
Plant: Apple (Miscellaneous Varieties)
Disease/Disorder: Fertility Issues (Suspected)
Pathogen: None
County: Wood
Plant: Apple (Miscellaneous Varieties)
Disease/Disorder: Frogeye Leaf Spot (Suspected)
Pathogen: Botryosphaeria obtusa
County: Wood
Plant: Apple (Miscellaneous Varieties)
Disease/Disorder: Sooty Blotch
Pathogen: Miscellaneous sooty blotch fungi
County: Wood
Herbaceous Ornamentals
Plant: Hosta
Disease/Disorder: Anthracnose
Pathogen: Colletotrichum sp.
County: Columbia
Plant: Hosta
Disease/Disorder: Foliar Nematode
Pathogen: Aphelenchoides sp.
County: Columbia
Plant: Hosta
Disease/Disorder: Southern Blight
Pathogen: Athelia rolsii
County: Dane
Plant: Iris (German Bearded)
Disease/Disorder: Bacterial Soft Rot
Pathogen: Pectobacterium sp.
County: Burnett
Plant: Wild Petunia
Disease/Disorder: Rust
Pathogen: Puccinia lateripes
County: Marathon
Houseplants
No New Diseases
Needled Woody Ornamentals
Plant: Fir (Fraser)
Disease/Disorder: Rhizosphaera Needle Cast
Pathogen: Rhizosphaera sp.
County: Adams
Plant: Spruce (Black Hills)
Disease/Disorder: Rhizosphaera Needle Cast
Pathogen: Rhizosphaera kalkhoffii
County: Portage
Plant: Spruce (Black Hills)
Disease/Disorder: Transplant Shock
Pathogen: None
County: Portage
Plant: Spruce (Unspecified)
Disease/Disorder: Spruce Needle Drop
Pathogen: Setomelanomma holmii
County: Fond du Lac
Vegetable Crops
Plant: Potato
Disease/Disorder: Gray Mold
Pathogen: Botrytis sp.
County: Waushara
Plant: Potato
Disease/Disorder: White Mold
Pathogen: Sclerotinia sclerotiorum
County: Waushara
Plant: Pumpkin
Disease/Disorder: Bacterial Wilt
Pathogen: Erwinia tracheiphila
County: Kenosha
Plant: Pumpkin
Disease/Disorder: Fusarium Crown Rot
Pathogen: Fusarium sp.
County: Kenosha
Plant: Pumpkin
Disease/Disorder: Powdery Mildew
Pathogen: Oidium sp.
County: Dane
Plant: Tomato
Disease/Disorder: Septoria Leaf Spot
Pathogen: Septoria lycopersici
County: Vernon
Specialty Crops
No New Diseases
Miscellaneous
No New Entries