Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from October 10, 2026 through October 16, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Aralia
Disease/Disorder:  Verticillium Wilt
Pathogen:  Verticillium sp.
County:  Walworth

Plant:  Oak (Northern Pin Oak)
Disease/Disorder:  Chlorosis
Pathogen:  None
County:  Dane

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

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Field Crops

Plant:  Corn
Disease/Disorder:  Chemical Burn (Suspected)
Pathogen:  None
Counties:  Eau Claire, Pierce

Plant:  Corn
Disease/Disorder:  Gibberella Stalk Rot
Pathogen:  Fusarium graminearum
County:  Green

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Forage Crops

No New Diseases

(Back To Menu)

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Fruit Crops

No New Diseases

(Back To Menu)

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Herbaceous Ornamentals

Plant:  Goldenrod (Stiff-Leaved)
Disease/Disorder:  Rhizoctonia Foliar Blight
Pathogen: Rhizoctonia sp.
County:  Rock

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Houseplants

No New Diseases

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Needled Woody Ornamentals

Plant:  Juniper
Disease/Disorder:  Cytospora Canker
Pathogen: Cytospora sp.
County:  Dane

Plant:  Juniper
Disease/Disorder:  Stagnospora Canker
Pathogen: Stagnospora sp.
County:  Dane

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Vegetable Crops

Plant:  Beet (Table)
Disease/Disorder:  Pythium Root Rot
Pathogen: Pythium sp.
County:  Columbia

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Specialty Crops

No New Diseases

(Back To Menu)

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Miscellaneous

No New Entries

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Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from October 3, 2026 through October 9, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Hydrangea
Disease/Disorder:  Root/Crown Rot
Pathogens:  Phytophthora sp., Rhizoctonia sp.
County:  Crawford

Plant:  Magnolia
Disease/Disorder:  Verticillium Wilt
Pathogen:  Verticillium sp.
County:  Dane

Plant:  Oak (Unspecified)
Disease/Disorder:  Chlorosis
Pathogen:  None
County:  Dane

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

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Field Crops

Plant:  Corn
Disease/Disorder:  Gibberella Stalk Rot
Pathogen:  Fusarium graminearum
County:  Rock

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Forage Crops

No New Diseases

(Back To Menu)

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Fruit Crops

Plant:  Apple
Disease/Disorder:  Chlorosis
Pathogen:  None
County:  Milwaukee

Plant:  Apple
Disease/Disorder:  Fertility Issues (Suspected)
Pathogen:  None
County:  Milwaukee

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Herbaceous Ornamentals

Plant:  Hosta
Disease/Disorder:  Anthracnose
Pathogen: Colletotrichum sp.
County:  Waukesha

Plant:  Hosta
Disease/Disorder:  Heat Stress (Suspected)
Pathogen: None
County:  Waukesha

Plant:  Pachysandra
Disease/Disorder:  Volutella Blight
Pathogen:  Volutella pachysandricola
County:  Waukesha

Plant:  Sedum
Disease/Disorder:  Anthracnose
Pathogen: Colletotrichum sp.
County:  Waukesha

Plant:  Sedum
Disease/Disorder:  Cercospora Leaf Spot
Pathogen:  Cercospora sp.
County:  Waukesha

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

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

Plant:  Arborvitae
Disease/Disorder:  Phyllosticta Needle Blight
Pathogen: Phyllosticta sp.
County:  Dane

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Vegetable Crops

No New Diseases

(Back To Menu)

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Specialty Crops

No New Diseases

(Back To Menu)

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Miscellaneous

No New Entries

(Back To Menu)

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Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from September 26, 2026 through October 2, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Beech (Unspecified)
Disease/Disorder:  Phytophthora Canker
Pathogen:  Phytophthora sp.
County:  Ozaukee

Plant:  Boxwood 
Disease/Disorder:  Fusarium Canker
Pathogen:  Fusarium sp.
County:  Washington

Plant:  Boxwood 
Disease/Disorder:  Volutella Canker
Pathogen:  Volutella sp.
County:  Washington

Plant:  Hydrangea
Disease/Disorder:  Anthracnose
Pathogen:  Colletotrichum sp.
County:  Sheboygan

Plant:  Hydrangea
Disease/Disorder:  Septoria Leaf Spot
Pathogen:  Septoria sp.
County:  Sheboygan

Plant:  Hydrangea
Disease/Disorder:  Xanthomonas Leaf Blight
Pathogen:  Xanthomonas sp.
County:  Sheboygan

Plant:  Lilac
Disease/Disorder:  Septoria Leaf Spot
Pathogen:  Septoria sp.
County:  Waukesha

Plant:  Magnolia
Disease/Disorder:  Verticillium Wilt
Pathogen:  Verticillium sp.
County:  Dane

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

Plant:  Maple (Variegated)
Disease/Disorder:  Anthracnose
Pathogens:  Colletotrichum sp., Discula sp.
County:  Waukesha

Plant:  Oak (Black)
Disease/Disorder:  Oak Wilt
Pathogen:  Bretziella fagacearum
County:  Eau Claire

Plant:  Oak (Red)
Disease/Disorder:  Herbicide Damage
Pathogen:  None
County:  Walworth

Plant:  Oak (Red)
Disease/Disorder:  Tubakia Leaf Spot
Pathogen:  Tubakia sp.
County:  Walworth

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Field Crops

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

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Forage Crops

No New Diseases

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Fruit Crops

Plant:  Apple
Disease/Disorder:  Nectria Twig Blight
Pathogen:  Tubercularia sp./Nectria sp.
County:  Sawyer

Plant:  Apple
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Sawyer

Plant:  Apple
Disease/Disorder:  Glomerella Leaf Spot
Pathogen: Colletotrichum sp.
County:  Racine

Plant:  Apple (‘Golden Delicious’)
Disease/Disorder:  Necrotic Leaf Blotch
Pathogen: None
County:  Racine

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Herbaceous Ornamentals

Plant:  Chrysanthemum
Disease/Disorder:  Root/Crown Rot
Pathogen: Rhizoctonia sp.
County:  Columbia

Plant:  Hosta
Disease/Disorder:  Hosta Virus X
Pathogen: Hosta virus X
County:  Door

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

Plant:  Spruce (Blue)
Disease/Disorder:  Rhizosphaera Needle Cast
Pathogen: Rhizosphaera kalkhoffii
County:  DuPage (IL)

Plant:  Spruce (Unspecified)
Disease/Disorder:  Phomopsis Canker
Pathogen: Phomopsis sp.
County:  Trempealeau

Plant:  Spruce (Unspecified)
Disease/Disorder:  Rhizosphaera Needle Cast
Pathogen: Rhizosphaera kalkhoffii
County:  Trempealeau

(Back To Menu)

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Vegetable Crops

No New Diseases

(Back To Menu)

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Specialty Crops

No New Diseases

(Back To Menu)

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Miscellaneous

No New Entries

(Back To Menu)

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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

(Back To Menu)

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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

(Back To Menu)

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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

(Back To Menu)

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Needled Woody Ornamentals

No New Diseases

(Back To Menu)

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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

(Back To Menu)

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Specialty Crops

No New Diseases

(Back To Menu)

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Miscellaneous

No New Entries

(Back To Menu)

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Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from August 29, 2026 through September 4, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Lilac (Common)
Disease/Disorder:  Herbicide Damage
Pathogen:  None
County:  Washington

Plant:  Maple (Unspecified)
Disease/Disorder:  Bleeding Canker/Root Rot/Crown Rot
Pathogen:  Phytophthora sp.
County:  Dane

Plant:  Musclewood
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Dane

Plant:  Oak (Bur)
Disease/Disorder:  Anthracnose
Pathogen:  Discula sp.
County:  Dane

Plant:  Oak (Bur)
Disease/Disorder:  Oak Wilt
Pathogen:  Bretziella fagacearum
County:  Dane

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

Plant:  Oak (Unspecified)
Disease/Disorder:  Herbicide Damage
Pathogen:  None
County:  Dane

Plant:  Oak (Unspecified)
Disease/Disorder:  Tubakia Leaf Spot
Pathogen:  Tubakia sp.
County:  Dane

Plant:  Pear (Ornamental)
Disease/Disorder:  Fire Blight
Pathogen:  Erwinia amylovora
Counties:  Dane, Waukesha

Plant:  Sycamore (American)
Disease/Disorder:  Frost Crack
Pathogen:  None
County:  La Crosse

Plant:  Sycamore (American)
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  La Crosse

Plant:  Walnut (Black)
Disease/Disorder:  Phyllosticta Leaf Spot
Pathogen:  Phyllosticta sp.
County:  Portage

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Field Crops

Plant:  Sorghum
Disease/Disorder:  Phytoplasma Disease
Pathogen:  Unspecified Phytoplasma
County:  Dane

Plant:  Soybean 
Disease/Disorder:  Brown Stem Rot
Pathogen:  Phialophora gregata
Counties:  Columbia, Racine

Plant:  Soybean
Disease/Disorder:  Sudden Death Syndrome
Pathogen:  Neocosmospora phaseoli
Counties:  Columbia, Green Lake, Racine

(Back To Menu)

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Forage Crops

No New Diseases

(Back To Menu)

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Fruit Crops

Plant:  Apple
Disease/Disorder:  Fire Blight
Pathogen:  Erwinia amylovora
County:  Sawyer

Plant:  Apple
Disease/Disorder:  Flyspeck
Pathogen: Zygophiala jamaicensis
County:  La Crosse

Plant:  Apple
Disease/Disorder:  Frogeye Leaf Spot
Pathogen: Botryosphaeria obtusa
County:  La Crosse

Plant:  Apple
Disease/Disorder:  Gymnosporangium Rust
Pathogen: Gymnosporangium sp.
County:  La Crosse

Plant:  Apple
Disease/Disorder:  Honeycrisp Leaf Mottle
Pathogen: None
Counties:  La Crosse, Sawyer

Plant:  Apple
Disease/Disorder:  Marssonina Leaf Blotch
Pathogen:  Marssonina coronaria
County:  La Crosse

Plant:  Apple
Disease/Disorder:  Powdery Mildew
Pathogen: Oidium sp.
County:  Sawyer

Plant:  Apple
Disease/Disorder:  Sooty Blotch
Pathogen:   Zygophiala jamaicensis
County:  La Crosse

Plant:  Strawberry
Disease/Disorder:  Root Rot
Pathogen:  Cylindrocarpon sp.
County:  Columbia

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Herbaceous Ornamentals

Plant:  Chrysanthemum
Disease/Disorder:  Crown Gall
Pathogen:  Agrobacterium tumefaciens
County:  Dodge

Plant:  Coleus
Disease/Disorder:  Downy Mildew
Pathogen:  Peronospora choii
County:  Jefferson

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

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

Plant:  False Indigo
Disease/Disorder:  Crown Gall
Pathogen:  Agrobacterium tumefaciens
County:  Ottawa (MI)

Plant:  False Indigo
Disease/Disorder:  Leafy Gall
Pathogen:  Rhodococcus facians
County:  Ottawa (MI)

Plant:  Fan Flower
Disease/Disorder:  Root Rot
Pathogen:  Phytophthora sp., Pythium sp.
County:  Bayfield

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

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

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

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

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

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

(Back To Menu)

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

Plant:  Arborvitae
Disease/Disorder:  Phyllosticta Canker
Pathogen:  Phyllosticta sp.
County:  Waukesha

Plant:  Fir
Disease/Disorder:  Cytospora Canker
Pathogen:  Cytospora sp.
County:  Dane

Plant:  Fir
Disease/Disorder:  Fertility Issues (Suspected)
Pathogen:  None
County:  Dane

Plant:  Pine (White)
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Dane

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Vegetable Crops

Plant:  Beet
Disease/Disorder:  Cercospora Leaf Spot
Pathogen:  Cercospora beticola
County:  Columbia

Plant:  Cabbage
Disease/Disorder:  Black Rot
Pathogen:  Xanthomonas campestris pv. campestris
County:  Waushara

Plant:  Cabbage
Disease/Disorder:  Fusarium Head Rot
Pathogen:  Fusarium sp.
County:  Waushara

Plant:  Cantaloupe
Disease/Disorder:  Alternaria Leaf Blight
Pathogen:  Alternaria cucumerina
County:  Grant

Plant:  Onion
Disease/Disorder:  Sour Skin (Suspected)
Pathogen:  Burkholderia cepacia
County:  Marquette

Plant:  Onion
Disease/Disorder:  Stemphylium Leaf Blight
Pathogen:  Stemphylium sp.
County:  Marquette

Plant:  Potato
Disease/Disorder:  Bacterial Soft Rot
Pathogen:  Dickeya dianthicola, Pectobacterium atrosepticum, Pectobacterium carotovorum subsp. carotovorum, Pectobacterium parmentieri
Counties:  Adams, Portage, Waushara

Plant:  Potato
Disease/Disorder:  Black Dot
Pathogen:  Colletotrichum coccodes
County:  Waushara

Plant:  Potato
Disease/Disorder:  Leak
Pathogen:  Pythium sp.
County:  Portage

Plant:  Tomato
Disease/Disorder:  Root Rot
Pathogen:  Pythium sp.
County:  Vilas

(Back To Menu)

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Specialty Crops

No New Diseases

(Back To Menu)

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Miscellaneous

No New Entries

(Back To Menu)

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Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from August 22, 2026 through August 28, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Crabapple
Disease/Disorder:  Botryosphaeria Canker
Pathogen:  Botryosphaeria sp.
County:  Dane

Plant:  Maple (Unspecified)
Disease/Disorder:  Girdling Root (Suspected)
Pathogen:  None
County:  Dane

Plant:  Maple (Unspecified)
Disease/Disorder:  Overly Deep Planting
Pathogen:  None
County:  Dane

Plant:  Oak (Bur)
Disease/Disorder:  Oak Wilt
Pathogen:  Bretziella fagacearum
County:  Rock

Plant:  Oak (Red)
Disease/Disorder:  Chlorosis
Pathogen:  None
Counties:  Milwaukee, Waukesha

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

Plant:  Willow (Purple Osier)
Disease/Disorder:  Botryosphaeria Canker
Pathogen:  Botryosphaeria sp.
County:  Marathon

Plant:  Willow (Purple Osier)
Disease/Disorder:  Cytospora Canker
Pathogen:  Cytospora sp.
County:  Marathon

(Back To Menu)

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Field Crops

Plant:  Corn (Field)
Disease/Disorder:  Drought Stress (Suspected)
Pathogen:  None
County:  Sauk

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

Plant:  Corn (Seed)
Disease/Disorder:  Common Rust
Pathogen:  Puccinia sorghi
County:  Grant

Plant:  Corn (Seed)
Disease/Disorder:  Gray Leaf Spot
Pathogen:  Cercospora sp.
County:  Grant

Plant:  Corn (Seed)
Disease/Disorder:  Norther Corn Leaf Blight
Pathogen:  Setosphaeria turcica 
County:  Grant

Plant:  Corn (Seed)
Disease/Disorder:  Purple Leaf Sheath
Pathogen:  None
County:  Grant

Plant:  Corn (Seed)
Disease/Disorder:  Southern Rust
Pathogen:  Puccinia polysora
County:  Grant

Plant:  Corn (Seed)
Disease/Disorder:  Drought Stress (Suspected)
Pathogen:  None
County:  Grant

(Back To Menu)

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Forage Crops

No New Diseases

(Back To Menu)

---

Fruit Crops

No New Diseases

(Back To Menu)

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Herbaceous Ornamentals

Plant:  Bulrush (Hard Stem)
Disease/Disorder:  Root Rot
Pathogen:  Fusarium sp.
County:  Rock

Plant:  Bulrush (Hard Stem)
Disease/Disorder:  Helminthosporium Leaf Spot
Pathogen:  Helminthosporium sp.
County:  Rock

Plant:  Bulrush (Hard Stem)
Disease/Disorder:  Septoria Leaf Spot
Pathogen:  Septoria sp.
County:  Rock

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

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

Plant:  Hosta
Disease/Disorder:  Tobacco Rattle
Pathogen:  Tobacco rattle virus
County:  Buffalo

(Back To Menu)

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

Plant:  Arborvitae
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Waukesha

Plant:  Arborvitae
Disease/Disorder:  Phyllosticta Canker
Pathogen:  Phyllosticta sp.
County:  Waukesha

Plant:  Juniper
Disease/Disorder:  Cytospora Canker
Pathogen:  Cytospora sp.
County:  Kenosha

Plant:  Juniper
Disease/Disorder:  Diplodia Shoot Blight and Canker
Pathogen:  Diplodia sp.
County:  Rock

Plant:  Juniper
Disease/Disorder:  Gymnosporangium Rust
Pathogen:  Gymnosporangium sp.
County:  Kenosha

Plant:  Juniper
Disease/Disorder:  Phomopsis Tip Blight
Pathogen:  Phomopsis sp.
County:  Rock

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Vegetable Crops

Plant:  Carrot
Disease/Disorder:  Bacterial Leaf Blight
Pathogen:  Xanthomonas sp.
County:  Waushara

Plant:  Corn (Sweet)
Disease/Disorder:  Anthracnose Stalk Rot
Pathogen:  Colletotrichum graminicola
County:  Dodge (MN)

Plant:  Corn (Sweet)
Disease/Disorder:  Fusarium Stalk Rot
Pathogen:  Fusarium sp.
County:  Dodge (MN)

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Specialty Crops

No New Diseases

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Miscellaneous

No New Entries

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Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from August 15, 2026 through August 21, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Ash (Unspecified)
Disease/Disorder:  Cylindrosporium Leaf Spot
Pathogen:  Cylindrosporium sp.
County:  Eau Claire

Plant:  Crabapple
Disease/Disorder:  Fire Blight
Pathogen:  Erwinia amylovora
Counties:  Eau Claire, Lincoln

Plant:  Lilac
Disease/Disorder:  Septoria Leaf Spot
Pathogen:  Septoria sp.
County:  Waukesha

Plant:  Magnolia
Disease/Disorder:  Root Rot
Pathogen:  Pythium sp.
County:  Waukesha

Plant:  Maple (Unspecified)
Disease/Disorder:  Anthracnose
Pathogen:  Discula sp. 
County:  La Crosse

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

Plant:  Oak (White)
Disease/Disorder:  Chlorosis
Pathogen:  None
County:  Waukesha

Plant:  Oak (White)
Disease/Disorder:  Coryneum Canker
Pathogen:  Coryneum sp.
County:  Waukesha

Plant:  Oak (Unspecified)
Disease/Disorder:  Oak Wilt
Pathogen:  Bretziella fagacearum
Counties:  Brown, Washburn

Plant:  Oak (Unspecified)
Disease/Disorder:  Root Rot
Pathogen:  Phytophthora sp.
County:  Waukesha

Plant:  Rose
Disease/Disorder:  Rose Rosette
Pathogen:  Rose rosette virus
County:  Milwaukee

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Field Crops

Plant:  Corn
Disease/Disorder:  Southern Rust
Pathogen:  Puccinia polysora
County:  Outagamie

Plant:  Soybean
Disease/Disorder:  Anthracnose
Pathogen:  Colletotrichum sp.
County:  Dodge

Plant:  Soybean
Disease/Disorder:  Downy Mildew
Pathogen:  Peronospora manshurica
County:  Dodge

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

Plant:  Soybean
Disease/Disorder:  Phytophthora Root and Stem Rot
Pathogen:  Phytophthora sp.
County:  Dodge

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

Plant:  Soybean
Disease/Disorder:  Sudden Death Syndrome
Pathogen:  Neocosmospora phaseoli
County:  Sauk

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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:  Milwaukee

Plant:  Apple (Unspecified)
Disease/Disorder:  Chemical Burn (Suspected)
Pathogen:  None
County:  Milwaukee

Plant:  Apple (Unspecified)
Disease/Disorder:  Frogeye Leaf Spot
Pathogen:  Botryosphaeria obtusa
County:  Dane

Plant:  Grape
Disease/Disorder:  Botryosphaeria Dieback
Pathogen:  Botryosphaeria sp.
County:  Dane

Plant:  Pear
Disease/Disorder:  Bitter Rot
Pathogen:  Colletotrichum sp.
County:  Walworth

Plant:  Strawberry
Disease/Disorder:  Root/Crown Rot
Pathogen:  Rhizoctonia sp., Fusarium sp.
Counties:  Anoka (MN), Dakota (MN)

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Herbaceous Ornamentals

Plant:  Chrysanthemum
Disease/Disorder:  Crown Gall
Pathogen:  Agrobacterium tumefaciens
County:  Clark

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

Plant:  Hosta
Disease/Disorder:  Sunburn (Suspected)
Pathogen:  None
County:  Milwaukee

Plant:  Hosta
Disease/Disorder:  Tobacco Rattle
Pathogen:  Tobacco rattle virus
County:  Buffalo

Plant:  Little Bluestem
Disease/Disorder:  Curvularia Blight
Pathogen:  Curvularia sp.
County:  Rock

Plant:  Little Bluestem
Disease/Disorder:  Helminthosporium Leaf Spot
Pathogen:  Helminthosporium sp.
County:  Rock

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Houseplants

No New Diseases

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Needled Woody Ornamentals

Plant:  Juniper
Disease/Disorder:  Root Rot
Pathogen:  Phytophthora sp.
County:  Waukesha

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Vegetable Crops

Plant:  Onion
Disease/Disorder:  Stemphylium Leaf Blight
Pathogen:  Stemphylium sp.
County:  Dane

Plant:  Potato
Disease/Disorder:  Bactieral Soft Rot
Pathogen:  Pectobacterium atrosepticum, Pectobacterium carotovorum subsp. carotovorum, Pectobacterium parmentieri
Counties:  Dane, Waushara

Plant:  Potato
Disease/Disorder:  Black Scurf
Pathogen:  Rhizoctonia solani
County:  Adams

Plant:  Potato
Disease/Disorder:  Fusarium Dry Rot
Pathogen:  Fusarium sp.
Counties:  Adams, Dane  

Plant:  Potato
Disease/Disorder:  Pythium Leak
Pathogen:  Pythium sp.
County:  Dane

Plant:  Tomato (Cherry)
Disease/Disorder:  Bacterial Canker
Pathogen:  Clavibacter michiganensis subsp. michiganensis
County:  Boone (IL)

Plant:  Tomato (Unspecified)
Disease/Disorder:  Bacterial Canker
Pathogen:  Clavibacter michiganensis subsp. michiganensis
County:  Dane

Plant:  Tomato (Unspecified)
Disease/Disorder:  Septoria Leaf Spot
Pathogen:  Septoria lycopersici
County:  Dane

Plant:  Tomato (Unspecified)
Disease/Disorder:  Verticillium Wilt
Pathogen:  Verticillium sp.
County:  Dane

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Specialty Crops

Plant:  Peppermint
Disease/Disorder:  Verticillium Wilt
Pathogen:  Verticillium sp.
County:  Rock

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Miscellaneous

No New Entries

(Back To Menu)

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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.

 

 

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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

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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

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Forage Crops

No New Diseases

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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

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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

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Houseplants

No New Diseases

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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

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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

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Specialty Crops

Plant:  Peppermint
Disease/Disorder:  Verticillium Wilt
Pathogen:  Verticillium sp.
County:  Rock

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Miscellaneous

No New Entries

(Back To Menu)

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Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from August 1, 2026 through August 7, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Boxwood
Disease/Disorder:  Volutella Canker
Pathogen:  Volutella sp.
County:  Waukesha

Plant:  Lilac (Common)
Disease/Disorder:  Septoria Leaf Spot
Pathogen:  Septoria sp.
County:  Dane

Plant:  Oak (Red)
Disease/Disorder:  Oak Wilt
Pathogen:  Bretziella fagacearum
Counties:  Dane, Columbia, Waukesha

Plant:  Oak (Unspecified)
Disease/Disorder:  Chlorosis
Pathogen:  None
County:  Sheboygan

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

Plant:  Oak (Unspecified)
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Dane

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Field Crops

No New Diseases

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Forage Crops

No New Diseases

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Fruit Crops

No New Diseases

(Back To Menu)

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Herbaceous Ornamentals

Plant:  Chrysanthemum
Disease/Disorder:  Crown Gall
Pathogen:  Agrobacterium tumefaciens
County:  Marathon

Plant:  Chrysanthemum
Disease/Disorder:  Root Rot
Pathogen:  Fusarium sp.
County:  Marathon

Plant:  Grass (Unspecified)
Disease/Disorder:  Ergot
Pathogen:  Claviceps purpureum
County:  Jefferson

Plant:  Hosta
Disease/Disorder:  Hosta Virus X
Pathogen:  Hosta virus X
County:  Door

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

Plant:  Arborvitae
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Milwaukee

Plant:  Arborvitae
Disease/Disorder:  Root Rot
Pathogen:  Fusarium oxysporum
County:  Dane

Plant:  Spruce (Unspecified)
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Waupaca

Plant:  Spruce (Unspecified)
Disease/Disorder:  Rhizosphaera Needle Cast
Pathogen:  Rhizosphaera kalkhoffii
County:  Waupaca

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Vegetable Crops

Plant:  Cucumber
Disease/Disorder:  Anthracnose
Pathogen:  Colletotrichum orbiculare
County:  Brown

Plant:  Pea
Disease/Disorder:  Fusarium Wilt
Pathogen:  Fusarium oxysporum
County:  Price

Plant:  Pea
Disease/Disorder:  Root Rot
Pathogen:  Rhizoctonia sp.
County:  Price

Plant:  Potato
Disease/Disorder:  Early Blight
Pathogen:  Alternaria solani
County:  Buffalo

Plant:  Pumpkin
Disease/Disorder:  Root Rot
Pathogen:  Rhizoctonia sp.
County:  Dane

Plant:  Tomato
Disease/Disorder:  Early Blight
Pathogen:  Alternaria solani
County:  Buffalo

Plant:  Tomato
Disease/Disorder:  Septoria Leaf Spot
Pathogen:  Septoria lycopersici
Counties:  Brown, Buffalo

Plant:  Watermelon
Disease/Disorder:  Cercospora Leaf Spot
Pathogen:  Cercospora sp.
County:  Vernon

Plant:  Watermelon
Disease/Disorder:  Cucumber Mosaic
Pathogen:  Cucumber mosaic virus
County:  Vernon

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Specialty Crops

No New Diseases

(Back To Menu)

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Miscellaneous

No New Entries

(Back To Menu)

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Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from July 25, 2026 through July 31, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Boxwood
Disease/Disorder:  Fusarium Canker
Pathogen:  Fusarium sp.
County:  Waukesha

Plant:  Boxwood
Disease/Disorder:  Volutella Canker
Pathogen:  Volutella sp.
County:  Waukesha

Plant:  Magnolia
Disease/Disorder:  Verticillium Wilt
Pathogen:  Verticillium sp.
County:  Dane

Plant:  Oak (Bur)
Disease/Disorder:  Oak Wilt
Pathogen:  Bretziella fagacearum
County:  Dane

Plant:  Oak (Red)
Disease/Disorder:  Chlorosis
Pathogen:  None
County:  Waukesha

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

Plant:  Oak (White)
Disease/Disorder:  Anthracnose
Pathogen:  Discula sp.
County:  Walworth

Plant:  Oak (White)
Disease/Disorder:  Tubakia Leaf spot
Pathogen:  Tubakia dryina
County:  Walworth

Plant:  Oak (Unspecified)
Disease/Disorder:  Oak Wilt
Pathogen:  Bretziella fagacearum
Counties:  Oneida, Waukesha

Plant:  Spirea
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Kenosha

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Field Crops

Plant:  Corn
Disease/Disorder:  Southern Rust
Pathogen:  Puccinia polysora
Counties:  Chippewa, Jackson, Trempealeau

Plant:  Soybean
Disease/Disorder:  Charcoal Rot
Pathogen:  Macrophomina phaseolina
County:  Fond du Lac

Plant:  Soybean
Disease/Disorder:  Fusarium Root Rot
Pathogen:  Fusarium sp.
County:  Fond du Lac

Plant:  Soybean
Disease/Disorder:  Phytophthora Root and Stem Rot
Pathogen:  Phytophthora sp.
Counties:  Calumet, Fond du Lac

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Forage Crops

No New Diseases

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Fruit Crops

Plant:  Cranberry
Disease/Disorder:  Upright Dieback
Pathogen:  Phomopsis vaccinii
County:  Price

Plant:  Strawberry
Disease/Disorder:  Root/Crown Rot
Pathogen:  Fusarium sp.
County:  Washington

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Herbaceous Ornamentals

Plant:  Daisy (Shasta)
Disease/Disorder:  Crown Gall
Pathogen:  Agrobacterium tumefaciens
County:  Ottawa (MI)

Plant:  Daisy (Shasta)
Disease/Disorder:  Leafy Gall
Pathogen:  Rhodococcus facians
County:  Ottawa (MI)

Plant:  Lisianthus
Disease/Disorder:  Alternaria spot/blight
Pathogen:  Alternaria sp.
County:  Dane

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Houseplants

No New Diseases

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Needled Woody Ornamentals

Plant:  Arborvitae
Disease/Disorder:  Root Rot
Pathogens:  Phytophthora sp., Pythium sp.
County:  Dane

Plant:  Pine (White)
Disease/Disorder:  White Pine Blister Rust
Pathogen:  Cronartium ribicola
County:  Washington

Plant:  Spruce (Norway)
Disease/Disorder:  Cytospora Canker
Pathogen:  Cytospora sp.
County:  Dane

Plant:  Yew
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Milwaukee

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Vegetable Crops

Plant:  Onion
Disease/Disorder:  Heat Stress (Suspected)
Pathogen:  None
County:  Dodge

Plant:  Onion
Disease/Disorder:  Root Rot
Pathogen:  Pythium sp.
County:  Green Lake

Plant:  Potato
Disease/Disorder:  Early Blight
Pathogen:  Alternaria solani
County:  Dane

Plant:  Potato
Disease/Disorder:  Walnut Toxicity (Suspected)
Pathogen:  Suspected
County:  Dane

Plant:  Pumpkin
Disease/Disorder:  Charcoal Rot
Pathogen:  Macrophomina phaseolina
County:  Portage

Plant:  Pumpkin
Disease/Disorder:  Fusarium Crown and Root Rot
Pathogen:  Fusarium sp.
County:  Portage

Plant:  Pumpkin
Disease/Disorder:  Phytophthora Crown and Root Rot
Pathogen:  Phytophthora sp.
County:  Portage

Plant:  Tomato
Disease/Disorder:  Early Blight
Pathogen:  Alternaria solani
County:  Dane

Plant:  Tomato
Disease/Disorder:  Walnut Toxicity (Suspected)
Pathogen:  Suspected
County:  Dane

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Specialty Crops

No New Diseases

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Miscellaneous

No New Entries

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