Compiled by Brian Hudelson and Dante Tauscheck
The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from September 20, 2025 through September 26, 2025.
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Broad-Leafed Woody Ornamentals
Plant: Birch (Paper)
Disease/Disorder: Septoria Leaf Spot
Pathogen: Septoria sp.
County: Door
Plant: Crabapple
Disease/Disorder: Gymnosporangium Rust
Pathogen: Gymnosporangium sp.
County: St. Croix
Plant: Crabapple
Disease/Disorder: Marssonina Blotch
Pathogen: Marssonina coronaria
County: St. Croix
Plant: Lilac (Japanese Tree)
Disease/Disorder: Verticillium Wilt
Pathogen: Verticillium sp.
County: Kenosha
Plant: Lilac (Shrub)
Disease/Disorder: Septoria Leaf Spot
Pathogen: Septoria sp.
County: Racine
Plant: Magnolia
Disease/Disorder: Anthracnose
Pathogen: Colletotrichum sp.
County: Brown
Plant: Magnolia
Disease/Disorder: Phoma Leaf Spot
Pathogen: Phoma sp.
County: Brown
Plant: Oak (Bur)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
County: Kenosha
Plant: Oak (Bur)
Disease/Disorder: Construction Injury
Pathogen: None
County: Dane
Plant: Oak (Bur)
Disease/Disorder: Monochaetia Leaf Spot
Pathogen: Monochaetia sp.
County: Kenosha
Plant: Oak (Bur)
Disease/Disorder: Tubakia Leaf Spot
Pathogen: Tubakia dryina
Counties: Dane, Eau Claire, Milwaukee
Plant: Oak (Pin)
Disease/Disorder: Chlorosis
Pathogen: None
County: Winnebago
Plant: Oak (Red)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
Counties: Green Lake, Kenosha, Walworth
Plant: Oak (Red)
Disease/Disorder: Chlorosis
Pathogen: None
Counties: Green Lake, Kenosha, Sheboygan
Plant: Oak (Red)
Disease/Disorder: Herbicide Damage
Pathogen: None
County: Kenosha
Plant: Oak (Red)
Disease/Disorder: Tubakia Leaf Spot
Pathogen: Tubakia dryina
Counties: Kenosha, Walworth
Plant: Sweet Shrub
Disease/Disorder: Root Rot
Pathogens: Phytophthora sp., Fusarium sp., Cylindrocarpon sp.
County: Dane
Field Crops
Plant: Corn (Field)
Disease/Disorder: Root Rot
Pathogen: Fusarium sp.
County: Portage
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Forage Crops
No New Diseases
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Fruit Crops
Plant: Apple (‘Honeycrisp’)
Disease/Disorder: Honeycrisp Leaf Mottle
Pathogen: None
County: Pierce
Plant: Apple (‘Honeycrisp’)
Disease/Disorder: Marssonina Blotch
Pathogen: Marssonina coronaria
County: Pierce
Plant: Apple (Unspecified)
Disease/Disorder: Bitter Pit/Cork Spot
Pathogen: None
County: Bayfield
Plant: Apple (Unspecified)
Disease/Disorder: Flyspeck
Pathogen: Zygophiala jamaicensis
County: Bayfield
Plant: Apple (Unspecified)
Disease/Disorder: Frogeye Leaf Spot
Pathogen: Botryosphaeria obtusa
County: Marathon
Plant: Apple (Unspecified)
Disease/Disorder: Marssonina Blotch
Pathogen: Marssonina coronaria
County: Marathon
Plant: Apple (Unspecified)
Disease/Disorder: Sooty Blotch
Pathogen: Miscellaneous sooty blotch fungi
County: Bayfield
Plant: Apple (Unspecified)
Disease/Disorder: Water Core
Pathogen: None
County: Bayfield
Plant: Cherry
Disease/Disorder: Cherry Leaf Spot
Pathogen: Blumeriella jaapii
County: Walworth
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Herbaceous Ornamentals
No New Diseases
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Houseplants
No New Diseases
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Needled Woody Ornamentals
Plant: Fir (Fraser)
Disease/Disorder: Root Rot
Pathogen: Phytophthora sp.
County: Door
Plant: Juniper
Disease/Disorder: Improper Planting
Pathogen: None
County: Dane
Plant: Juniper
Disease/Disorder: Transplant Shock
Pathogen: None
County: Dane
Plant: Juniper
Disease/Disorder: Stagnospora Canker
Pathogen: Stagnospora sp,
County: Waukesha
Plant: Pine (White)
Disease/Disorder: Chlorosis (Suspected)
Pathogen: None
County: Sheboygan
Plant: Pine (White)
Disease/Disorder: Seasonal Needle Drop
Pathogen: None
County: Dane
Plant: Spruce (Black Hills)
Disease/Disorder: Rhizosphaera Needle Cast
Pathogen: Rhizosphaera kalkhoffii
County: Shawano
Plant: Spruce (Black Hills)
Disease/Disorder: Transplant Issues
Pathogen: None
County: Shawano
Plant: Spruce (Black Hills)
Disease/Disorder: Water Stress
Pathogen: None
County: Shawano
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Vegetable Crops
Plant: Bean (Lima)
Disease/Disorder: Bacterial Brown Spot
Pathogen: Pseudomonas syringae pv. syringae
County: Waushara
Plant: Bean (Lima)
Disease/Disorder: Common Blight
Pathogen: Xanthomonas axonopodis pv. phaseoli
County: Waushara
Plant: Beet (Table)
Disease/Disorder: Cercospora Leaf Spot
Pathogen: Cercospora beticola
County: Columbia
Plant: Potato
Disease/Disorder: White Mold
Pathogen: Sclerotinia sclerotiorum
County: Langlade
Plant: Pumpkin
Disease/Disorder: Plectosporium Blight
Pathogen: Plectosphaerella cucumerina
County: Dane
Plant: Squash (Unspecified)
Disease/Disorder: Squash Mosaic
Pathogen: Squash mosaic virus
County: Dane
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Specialty Crops
No New Diseases
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Miscellaneous
Fungus ID: Artillery Fungus (Sphaerabolus sp.)
County: Dane
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