Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from September 19, 2026 through September 25, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Aspen
Disease/Disorder:  Septoria Leaf Spot
Pathogen:  Septoria sp. (Sphaerulina sp.)
County:  Dane

Plant:  Beech (European)
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Milwaukee

Plant:  Elm (Unspecified)
Disease/Disorder:  Dutch Elm Disease
Pathogen:  Ophiostoma sp.
County:  Cook (IL)

Plant:  Maple (Japanese)
Disease/Disorder:  Verticillium Wilt
Pathogen:  Verticillium sp.
County:  Dane

Plant:  Oak (Bur)
Disease/Disorder:  Tubakia Leaf Spot
Pathogen:  Tubakia sp.
County:  Vernon

Plant:  Oak (Red)
Disease/Disorder:  Oak Wilt
Pathogen:  Bretziella fagacearum
County:  Brown

Plant:  Oak (Unspecified)
Disease/Disorder:  Oak Wilt
Pathogen:  Bretziella fagacearum
County:  Waukesha

Plant:  Pear (Ornamental)
Disease/Disorder:  Fire Blight
Pathogen:  Erwinia amylovora
County:  Waukesha

Plant:  Willow (Dappled)
Disease/Disorder:  Botryosphaeria Canker
Pathogen:  Botryosphaeria sp.
County:  Dane

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Field Crops

Plant:  Corn
Disease/Disorder:  Gibberella Ear Rot
Pathogen:  Gibberella zeae (Fusarium graminearum)
County:  Sauk

Plant:  Corn
Disease/Disorder:  Gray Leaf Spot
Pathogen:  Cercospora sp.
County:  Sauk

Plant:  Corn
Disease/Disorder:  Northern Corn Leaf Blight
Pathogen:  Exserohilum turcicum
County:  Sauk

Plant:  Soybean 
Disease/Disorder:  Cercospora Leaf Blight
Pathogen:  Cercospora kikuchii
County:  Rusk

Plant:  Soybean
Disease/Disorder:  Charcoal Rot
Pathogen:  Macrophomina phaseolina
County:  Jefferson

Plant:  Soybean
Disease/Disorder:  Fusarium Root Rot
Pathogen:  Fusarium sp.
County:  Rock

Plant:  Soybean
Disease/Disorder:  Stem Canker
Pathogen:  Diaporthe phaseolorum
County:  Jefferson

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Forage Crops

No New Diseases

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Fruit Crops

Plant:  Cranberry
Disease/Disorder:  Bitter Rot
Pathogen:  Colletotrichum sp.
County:  Monroe

Plant:  Grape
Disease/Disorder:  Black Rot
Pathogen: Guignardia bidwellii
County:  Waushara

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Herbaceous Ornamentals

Plant:  Bluestar (Unspecified)
Disease/Disorder:  Crown Gall
Pathogen:  Agrobacterium tumefaciens
County:  Ottawa (MI)

Plant:  Hosta
Disease/Disorder:  Potyvirus Disease
Pathogen:  Unspecified potyvirus
County:  Pepin

Plant:  Indian Plantain (Pale)
Disease/Disorder:  Tomato Spotted Wilt
Pathogen:  Tomato spotted wilt virus
County:  Marquette

Plant:  Peony
Disease/Disorder:  Root/Crown Rot
Pathogen:  Phytophthora sp.
County:  Brown

Plant:  Sedum
Disease/Disorder:  Powdery Mildew
Pathogen:  Oidium sp.
County:  Washington

Plant:  Speedwell (Unspecified)
Disease/Disorder:  Crown Gall
Pathogen:  Agrobacterium tumefaciens
County:  Ottawa (MI)

Plant:  Speedwell (Unspecified)
Disease/Disorder:  Leafy Gall
Pathogen:  Rhodococcus facians
County:  Ottawa (MI)

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Houseplants

Plant:  African Mask Plant
Disease/Disorder:  Root/Crown Rot
Pathogens:  Phtophthora sp., Fusarium sp.
County:  Kenosha

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Needled Woody Ornamentals

No New Diseases

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Vegetable Crops

Plant:  Lettuce
Disease/Disorder:  Bacterial Leaf Spot
Pathogen:  Xanthomonas sp.
County:  Aroostook (ME)

Plant:  Potato
Disease/Disorder:  Bacterial Soft Rot
Pathogen:  Pectobacterium atrosepticum, Pectobacterium carotovorum subsp. carotovorum
County:  Waushara

Plant:  Tomatillo
Disease/Disorder:  Cercospora Leaf Spot
Pathogen:  Cercospora sp.
County:  Dane

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Specialty Crops

No New Diseases

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Miscellaneous

No New Entries

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