Compiled by Brian Hudelson and Hulubanche Kassa
The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from August 8, 2026 through August 14, 2026.
Broad-Leafed Woody Ornamentals
Plant: Birch (River)
Disease/Disorder: Mouse Ear (Suspected)
Pathogen: None (Nickel Deficiency)
County: Door
Plant: Crabapple
Disease/Disorder: Apple Scab
Pathogen: Venturia inaequalis
County: Dane
Plant: Crabapple
Disease/Disorder: Red Star Rust
Pathogen: Gymnosporangium yamadae
County: Dane
Plant: Maple (Unspecified)
Disease/Disorder: Sunburn
Pathogen: None
County: Washington
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 (Unspecified)
Disease/Disorder: Chlorosis
Pathogen: None
Counties: Door, Outagamie
Field Crops
Plant: Soybean
Disease/Disorder: Downy Mildew
Pathogen: Peronospora manshurica
County: Portage
Plant: Soybean
Disease/Disorder: Fusarium Root Rot
Pathogen: Fusarium sp.
County: Portage
Plant: Soybean
Disease/Disorder: Phytophthora Root and Stem Rot
Pathogen: Phytophthora sp.
Counties: Portage, Waupaca
Plant: Soybean
Disease/Disorder: Pythium Root Rot
Pathogen: Pythium sp.
County: Waupaca
Plant: Soybean
Disease/Disorder: Soybean Cyst Nematode
Pathogen: Heterodera glycines
County: Portage
Forage Crops
No New Diseases
Fruit Crops
Plant: Apple
Disease/Disorder: Frogeye Leaf Spot
Pathogen: Botryosphaeria obtusa
County: Door
Plant: Blueberry
Disease/Disorder: Sphaeropsis Canker
Pathogen: Sphaeropsis sp.
County: McHenry (IL)
Plant: Cherry
Disease/Disorder: Cherry Leaf Spot
Pathogen: Blumeriella jaapii
County: Door
Plant: Peach
Disease/Disorder: Bacterial Leaf Spot
Pathogen: Xanthomonas arboricola pv. pruni
County: Door
Plant: Peach
Disease/Disorder: Peach Leaf Curl
Pathogen: Taphrina deformans
County: Door
Plant: Pear
Disease/Disorder: Transplant Shock (Suspected)
Pathogen: None
County: Ozaukee
Herbaceous Ornamentals
Plant: Hosta
Disease/Disorder: Tobacco Rattle
Pathogen: Tobacco rattle virus
County: Buffalo
Plant: Peony
Disease/Disorder: Gray Mold/Botrytis Blight
Pathogen: Botrytis sp.
County: Portage
Plant: Sedum
Disease/Disorder: Anthracnose
Pathogen: Colletotrichum sp.
County: Jefferson
Plant: Sedum
Disease/Disorder: Cercospora Leaf Spot
Pathogen: Cercospora sp.
County: La Crosse
Plant: Sedum
Disease/Disorder: Phytophthora Root/Crown Rot
Pathogen: Phytophthora sp.
County: Jefferson
Plant: Sedum
Disease/Disorder: Powdery Mildew
Pathogen: Oidium sp.
County: La Crosse
Plant: Sedum
Disease/Disorder: Rhizoctonia Root/Crown Rot
Pathogen: Rhizoctonia sp.
County: Jefferson
Plant: Sedum
Disease/Disorder: Sphaeropsis Canker
Pathogen: Sphaeropsis sp.
County: Jefferson
Plant: Sideoats Grama
Disease/Disorder: Bipolaris Leaf Spot
Pathogen: Bipolaris sp.
County: Rock
Houseplants
No New Diseases
Needled Woody Ornamentals
Plant: Juniper
Disease/Disorder: Diplodia Shoot Blight and Canker
Pathogen: Diplodia sp.
County: Waukesha
Plant: Juniper
Disease/Disorder: Gymnosporangium Rust
Pathogen: Gymnosporangium sp.
County: Waukesha
Plant: Spruce (Black Hills)
Disease/Disorder: Rhizosphaera Needle Cast
Pathogen: Rhizosphaera kalkhoffii
County: Green
Plant: Spruce (Blue)
Disease/Disorder: Rhizosphaera Needle Cast
Pathogen: Rhizosphaera kalkhoffii
County: Green
Plant: Yew
Disease/Disorder: Twig Blight
Pathogen: Phyllosticta sp.
County: Milwaukee
Vegetable Crops
Plant: Cabbage
Disease/Disorder: Black Rot
Pathogen: Xanthomonas campestis pv. campestris
County: Waushara
Plant: Lettuce (Romaine)
Disease/Disorder: Bactieral Leaf Spot
Pathogen: Xanthomonas campestis pv. vitians
County: Aroostook (ME)
Plant: Potato
Disease/Disorder: Verticillium Wilt
Pathogen: Verticillium sp.
County: Barron
Specialty Crops
Plant: Peppermint
Disease/Disorder: Verticillium Wilt
Pathogen: Verticillium sp.
County: Rock
Miscellaneous
No New Entries