Compiled by Brian Hudelson and Dante Tauscheck
The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from August 16, 2025 through August 22, 2025.
Page Table of Contents
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Broad-Leafed Woody Ornamentals
Plant: Beech (American)
Disease/Disorder: Chlorosis
Pathogen: None
County: Milwaukee
Plant: Birch (Gray)
Disease/Disorder: Chlorosis
Pathogen: None
County: Dane
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 (White)
Disease/Disorder: Anthracnose
Pathogen: Discula sp.
County: Dane
Plant: Oak (White)
Disease/Disorder: Chlorosis
Pathogen: None
County: Dane
Plant: Oak (White)
Disease/Disorder: Oak Wilt
Pathogen: Bretziella fagacearum
County: Dane
Plant: Oak (White)
Disease/Disorder: Tubakia Leaf Spot
Pathogen: Tubakia dryina
County: Dane
Plant: Oak (Unspecified)
Disease/Disorder: Chlorosis
Pathogen: None
County: Door
Plant: Oak (Unspecified)
Disease/Disorder: Oak Wilt
Pathogen: Bretziella fagacearum
Counties: Marathon, Sauk
Plant: Pear (Callery)
Disease/Disorder: Botryosphaeria Canker
Pathogen: Botryosphaeria sp.
County: Dane
Plant: Pear (Callery)
Disease/Disorder: Fire Blight
Pathogen: Erwinia amylovora
County: Dane
Plant: Serviceberry
Disease/Disorder: Chlorosis
Pathogen: None
County: Dane
Plant: Serviceberry
Disease/Disorder: Powdery Mildew
Pathogen: Oidium sp.
County: Dane
Plant: Smokebush
Disease/Disorder: Verticillium Wilt
Pathogen: Verticillium sp.
County: Dane
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Field Crops
Plant: Corn (Field)
Disease/Disorder: Southern Corn Rust
Pathogen: Puccinia polysora
Counties: Columbia, Grant, Iowa, Rock
Plant: Corn (Field)
Disease/Disorder: Tar Spot
Pathogen: Phyllachora maydis
Counties: Columbia, Grant, Iowa, Rock
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Forage Crops
Plant: Alfalfa
Disease/Disorder: Root Rot
Pathogen: Aphanomyces euteiches, Phytophthora sp., Pythium sp., Rhizoctonia sp., Fusarium sp.
County: Manitowoc
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Fruit Crops
Plant: Cranberry
Disease/Disorder: Bitter Rot
Pathogen: Colletotrichum gloeosporioides/Glomerella cingulata
County: Monroe
Plant: Grape
Disease/Disorder: Black Rot
Pathogen: Phyllosticta ampelicida
County: Dane
Plant: Grape
Disease/Disorder: Powdery Mildew
Pathogen: Oidium sp.
County: Dane
Plant: Grape
Disease/Disorder: Sour Rot
Pathogen: Miscellaneous yeasts
County: Dane
Plant: Peach
Disease/Disorder: Bacterial Canker
Pathogen: Pseudomonas syringae
County: Dane
Plant: Peach
Disease/Disorder: Cold Injury (Suspected)
Pathogen: None
County: Dane
Plant: Raspberry
Disease/Disorder: Root/Crown Rot
Pathogens: Phytophthora sp., Rhizoctonia sp.
County: Dane
Plant: Strawberry
Disease/Disorder: Root/Crown Rot
Pathogen: Rhizoctonia sp.
County: Dane
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Herbaceous Ornamentals
Plant: Amaranth
Disease/Disorder: Root/Crown Rot
Pathogen: Pythium sp.
County: Vernon
Plant: Gaillardia
Disease/Disorder: Aster Yellows (Suspected)
Pathogen: Aster Yellows Phytoplasma
County: Dane
Plant: Hosta
Disease/Disorder: Root/Crown Rot
Pathogen: Fusarium oxysporum
County: Waukesha
Plant: Phlox
Disease/Disorder: Anthracnose
Pathogen: Colletotrichum sp.
Counties: Bayfield, Brown
Plant: Phlox
Disease/Disorder: Powdery Mildew
Pathogen: Oidium sp.
County: Brown
Plant: Sunpatiens
Disease/Disorder: Herbicide Damage (Suspected)
Pathogen: None
County: Brown
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Houseplants
No New Diseases
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Needled Woody Ornamentals
Plant: Arborvitae
Disease/Disorder: Phomopsis Canker
Pathogen: Phomopsis sp.
County: Milwaukee
Plant: Juniper
Disease/Disorder: Winter Burn
Pathogen: None
County: Waukesha
Plant: Larch (Unspecified)
Disease/Disorder: Larch Needle Cast
Pathogen: Mycosphaerella laricina
County: Dane
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Vegetable Crops
Plant: Broccoli
Disease/Disorder: Root Rot
Pathogen: Pythium sp., Phytophthora sp., Fusarium oxysporum
County: Milwaukee
Plant: Cabbage (Napa)
Disease/Disorder: Head Rot
Pathogen: Rhizoctonia sp., Phytophthora sp.
County: Milwaukee
Plant: Corn (Sweet)
Disease/Disorder: Gray Leaf Spot
Pathogen: Cercospora sp.
County: Door
Plant: Kale
Disease/Disorder: Root Rot
Pathogen: Pythium sp., Phytophthora sp., Fusarium sp.
County: Milwaukee
Plant: Pepper
Disease/Disorder: Root Rot
Pathogen: Pythium sp., Phytophthora sp., Fusarium sp.
County: Milwaukee
Plant: Potato
Disease/Disorder: Black Leg
Pathogen: Pectobacterium carotovorum subsp. carotovorum
County: Waushara
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Specialty Crops
No New Diseases
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Miscellaneous
Mushroom ID: Jack O’Lantern Mushroom (Omphalotus illudens)
County: Dane
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