Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from May 16, 2026 through May 22, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Boxwood
Disease/Disorder:  Fusarium Canker
Pathogen:  Fusarium sp.
Counties:  Green, Waukesha

Plant:  Boxwood
Disease/Disorder:  Genetic Sport
Pathogen:  None
County:  Green

Plant:  Boxwood
Disease/Disorder:  Volutella Canker
Pathogen:  Volutella sp.
Counties:  Green, Waukesha

Plant:  Boxwood
Disease/Disorder:  Winter Burn
Pathogen:  None
County:  Green

Plant:  Cherry (Unspecified)
Disease/Disorder:  Black Knot
Pathogen:  Apiosporina morbosa
County:  Dane

Plant:  Crabapple
Disease/Disorder:  Apple Scab
Pathogen:  Venturia inaequalis
County:  Walworth

Plant:  Holly
Disease/Disorder:  Phoma Leaf Spot
Pathogen:  Phoma sp.
County:  Dane

Plant:  Holly
Disease/Disorder:  Septoria Leaf Spot
Pathogen:  Septoria sp.
County:  Dane

Plant:  Lilac
Disease/Disorder:  Anthracnose
Pathogen:  Gloeosporium sp.
County:  Dane

Plant:  Lilac
Disease/Disorder:  Root/Crown Rot
Pathogens:  Fusarium sp., Rhizoctonia sp.
County:  Dane

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

Plant:  Ninebark
Disease/Disorder:  Powdery Mildew
Pathogen:  Oidium sp.
Counties:  Dane, Waukesha

Plant:  Pear (Callery)
Disease/Disorder:  Tubercularia/Nectria Canker
Pathogens:  Tubercularia sp./Nectria sp.
County:  Dunn

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Field Crops

No New Diseases

(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:  Cold Injury (Suspected)
Pathogen:  None
County:  Jefferson

Plant:  Apple 
Disease/Disorder:  Cytospora Canker
Pathogen:  Cytospora sp.
County:  Waupaca

Plant:  Aronia
Disease/Disorder:  Transplant Shock (Suspected)
Pathogen:  None
County:  Dane

Plant:  Cherry
Disease/Disorder:  Bacterial Canker
Pathogen:  Pseudomonas syringae
County:  Dane

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Herbaceous Ornamentals

Plant:  Astilbe
Disease/Disorder:  Tobacco Rattle
Pathogens:  Tobacco rattle virus
County:  Jefferson

Plant:  Bleeding Heart
Disease/Disorder:  Tobacco Rattle
Pathogens:  Tobacco rattle virus
County:  Jefferson

Plant:  Hosta
Disease/Disorder:  Storm Damage (Suspected)
Pathogens:  None
County:  Brown

Plant:  Pachysandra
Disease/Disorder:  Volutella Blight
Pathogens:  Volutella pachysandricola
County:  Dane

Plant:  Peony
Disease/Disorder:  Septoria Leaf Spot
Pathogens:  Septoria sp.
County:  Dane

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

Plant:  Pine (White)
Disease/Disorder:  Transplant Shock (Suspected)
Pathogens:  None
County:  Dane

Plant:  Spruce (Black Hills)
Disease/Disorder:  Rhizosphaera Needle Cast
Pathogen:  Rhizosphaera kalkhoffii
County:  St. Croix

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

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

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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 May 9, 2026 through May 15, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Boxwood
Disease/Disorder:  Fusarium Canker
Pathogen:  Fusarium sp.
Counties:  Brown, Milwaukee, Waukesha

Plant:  Boxwood
Disease/Disorder:  Volutella Canker
Pathogen:  Volutella sp.
Counties:  Brown, Milwaukee, Waukesha

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

Plant:  Oak (Bur)
Disease/Disorder:  Bur Oak Blight
Pathogen:  Tubakia iowensis
County:  Waukesha

Plant:  Oak (Red)
Disease/Disorder:  Transplant Shock
Pathogen:  None
County:  Dane

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Field Crops

No New Diseases

(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:  Sphaeropsis Canker
Pathogen:  Sphaeropsis sp.
County:  Waukesha

Plant:  Currant (Black)
Disease/Disorder:  Septoria Leaf Spot
Pathogen:  Septoria ribis
County:  Iowa

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Herbaceous Ornamentals

Plant:  Dahlia
Disease/Disorder:  Dahlia Mosaic
Pathogens:  Dahlia mosaic virus
County:  Milwaukee

Plant:  Dahlia
Disease/Disorder:  Tomato Spotted Wilt
Pathogens:  Tomato spotted wilt virus
County:  Milwaukee

Plant:  Impatiens
Disease/Disorder:  Cucumber Mosaic
Pathogens:  Cucumber mosaic virus
County:  Dane

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Houseplants

No New Diseases

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Needled Woody Ornamentals

Plant:  Arborvitae
Disease/Disorder:  Rabbit Damage (Suspected)
Pathogens:  None
County:  Dane

Plant:  Fir (Fraser)
Disease/Disorder:  Root/Crown Rot
Pathogen:  Pythium sp.
County:  Lincoln

Plant:  Fir (Fraser)
Disease/Disorder:  Transplant Shock (Suspected)
Pathogen:  None
County:  Lincoln

Plant:  Fir (Fraser)
Disease/Disorder:  Winter Burn (Suspected)
Pathogen:  None
County:  Lincoln

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

Plant:  Juniper
Disease/Disorder:  Sphaeropsis Canker
Pathogen:  Sphaeropsis sp.
County:  Walworth

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

Plant:  Spruce (Unspecified)
Disease/Disorder:  Cytospora Canker
Pathogen:  Cytospora sp.
County:  Waukesha

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

Plant:  Yew
Disease/Disorder:  Twig Blight
Pathogen:  Phyllosticta sp.
County:  Dane

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Vegetable Crops

Plant:  Potato
Disease/Disorder:  Black Leg
Pathogen:  Dickeya dianthicola
County:  Waushara

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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 May 2, 2026 through May 8, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Cotoneaster
Disease/Disorder:  Root/Crown Rot
Pathogen:  Pythium sp.
County:  Walworth

Plant:  Walnut
Disease/Disorder:  Lichens
Pathogen:  None
County:  Richland

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Field Crops

No New Diseases

(Back To Menu)

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Forage Crops

No New Diseases

(Back To Menu)

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Fruit Crops

Plant:  Cherry (Sour)
Disease/Disorder:  Bacterial Canker
Pathogen:  Pseudomonas syringae
County:  Milwaukee

Plant:  Cherry (Sour)
Disease/Disorder:  Brown Rot
Pathogen:  Monilinia sp.
County:  Milwaukee

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Herbaceous Ornamentals

Plant:  Pussytoes
Disease/Disorder:  Root/Crown Rot
Pathogens:  Rhizoctonia sp.
County:  Rock

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

Plant:  Arborvitae
Disease/Disorder:  Root/Crown Rot
Pathogens:  Phytophthora sp., Fusarium sp.
County:  Waukesha

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Vegetable Crops

Plant:  Potato
Disease/Disorder:  Bacterial Soft Rot
Pathogen:  Pectobacterium carotorvorum subsp. carotovorum, Pectobacterium parmentieri
County:  St. Joseph (MI)

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

Plant:  Tomato
Disease/Disorder:  Gray Mold/Botrytis Blight
Pathogen:  Botrytis cinerea
County:  Vernon

Plant:  Tomato
Disease/Disorder:  Magnesium Deficiency (Suspected)
Pathogen:  None
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 Dante Tauscheck

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from April 25, 2026 through May 1, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Boxwood
Disease/Disorder:  Cold Injury (Suspected)
Pathogen:  None
Counties:  Ozaukee, Waukesha

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

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

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

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Field Crops

No New Diseases

(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:  Waupaca

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

Plant:  Pear
Disease/Disorder:  Fire Blight
Pathogen:  Erwinia amylovora
County:  Waupaca

Plant:  Pear
Disease/Disorder:  Sphaeropsis Canker
Pathogen:  Sphaeropsis sp.
County:  Waupaca

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Herbaceous Ornamentals

No New Diseases

(Back To Menu)

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

Plant:  Pine (Limber)
Disease/Disorder:  Dothistroma Needle Blight
Pathogen:  Dothistroma sp.
County:  Dane

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

Plant:  Spruce
Disease/Disorder: Rhizosphaera Needle Cast
Pathogen:  Rhizosphaera kalkhoffii
County:  Sheboygan

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Vegetable Crops

Plant:  Carrot
Disease/Disorder:  Aster Yellows
Pathogen:  Aster yellows phytoplasma
County:  Dane

Plant:  Carrot
Disease/Disorder:  Fusarium Canker
Pathogen:  Fusarium sp.
County:  Dane

Plant:  Pepper (Bell)
Disease/Disorder:  Tomato Spotted Wilt
Pathogen:  Tomato spotted wilt virus
County:  Will (IL)

Plant:  Pepper (Cayenne)
Disease/Disorder:  Bacterial Spot
Pathogen:  Xanthomonas sp.
County:  Will (IL)

Plant:  Pepper (Cayenne)
Disease/Disorder:  Tomato Spotted Wilt
Pathogen:  Tomato spotted wilt virus
County:  Will (IL)

Plant:  Potato
Disease/Disorder:  Bacterial Soft Rot
Pathogens:  Pectobacterium carotovorum subsp. carotovorum, Pectobacterium parmentieri
County:  Marathon

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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 Dante Tauscheck

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from April 18, 2026 through April 24, 2026.

 

 

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Broad-Leafed Woody Ornamentals

No New Diseases

(Back To Menu)

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Field Crops

No New Diseases

(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:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Winnebago

Plant:  Apple
Disease/Disorder:  Wood Rot (Suspected)
Pathogen:  Unidentified wood rot fungus
County:  Winnebago

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Herbaceous Ornamentals

No New Diseases

(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 Needle Blight
Pathogen:  Phyllosticta sp.
County:  Dane

Plant:  Arborvitae
Disease/Disorder:  Winter Burn
Pathogen:  Phomopsis sp.
County:  Dane

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Vegetable Crops

Plant:  Potato
Disease/Disorder:  Bacterial Soft Rot
Pathogen:  Pectobacterium sp.
County:  Adams

Plant:  Potato
Disease/Disorder:  Black Dot
Pathogen:  Colletotrichum coccodes
Counties:  Adams, Langlade

Plant:  Potato
Disease/Disorder:  Common Scab
Pathogen:  Streptomyces scabies
County:  Langlade

Plant:  Potato
Disease/Disorder:  Grey Leaf Spot
Pathogen:  Stemphylium sp.
County:  Sauk

Plant:  Potato
Disease/Disorder:  Silver Scurf
Pathogen:  Helminthosporium solani
Counties:  Adams, Langlade

Plant:  Watermelon
Disease/Disorder:  Damping-Off
Pathogens:  Rhizoctonia sp., Fusarium sp.
County:  Sauk

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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 Dante Tauscheck

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from April 11, 2026 through April 17, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Elm (American)
Disease/Disorder:  Dutch elm disease
Pathogen:  Ophiostoma sp.
County:  Jefferson

Plant:  Hickory
Disease/Disorder:  Wood rot (suspected)
Pathogen:  Unidentified wood rot fungus
County:  Dane

Plant:  Lilac
Disease/Disorder:  Root rot
Pathogens:  Pythium sp., Fusarium sp.
County:  Columbia

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Field Crops

No New Diseases

(Back To Menu)

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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:  Impatiens
Disease/Disorder:  Cucumber mosaic
Pathogen:  Cucumber mosaic virus
County:  Vernon

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

Plant:  Fir (White)
Disease/Disorder:  Phyllosticta needle blight
Pathogen:  Phyllosticta sp.
County:  DuPage (IL)

Plant:  Spruce (Norway)
Disease/Disorder:  Phomopsis Canker
Pathogens:  Phomopsis sp.
County:  DuPage (IL)

Plant:  Spruce (Norway)
Disease/Disorder:  Root rot
Pathogens:  Pythium sp.
County:  DuPage (IL)

(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 Dante Tauscheck

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from April 4, 2026 through April 10, 2026.

 

 

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Broad-Leafed Woody Ornamentals

No New Diseases

(Back To Menu)

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Field Crops

No New Diseases

(Back To Menu)

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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:  Sunflower
Disease/Disorder:  Powdery Mildew
Pathogen:  Oidium sp.
County:  Jefferson

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

Plant:  Spruce (Oriental)
Disease/Disorder:  Winter Burn
Pathogen:  None
County:  Dane

(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 Dante Tauscheck

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from March 28, 2026 through April 3, 2026.

 

 

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Broad-Leafed Woody Ornamentals

No New Diseases

(Back To Menu)

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Field Crops

No New Diseases

(Back To Menu)

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

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

No New Diseases

(Back To Menu)

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Vegetable Crops

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

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

Plant:  Potato
Disease/Disorder:  Silver Scurf
Pathogen:  Helminthosporium solani
County:  Portage

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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 Dante Tauscheck

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from March 21, 2026 through March 27, 2026.

 

 

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Broad-Leafed Woody Ornamentals

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

Plant:  Boxwood
Disease/Disorder:  Winter Burn (Suspected)
Pathogen:  None
County:  Milwaukee

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

Plant:  Rose
Disease/Disorder:  Pythium Canker
Pathogen: Pythium sp.
County:  Columbia

(Back To Menu)

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Field Crops

No New Diseases

(Back To Menu)

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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:  Dahlia
Disease/Disorder:  Crown Gall
Pathogen:  Agrobacterium tumefaciens
Counties:  La Crosse, Rock

Plant:  Black-Eyed Susan
Disease/Disorder:  Septoria Leaf Spot
Pathogen:  Septoria sp.
County:  Waukesha

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

No New Diseases

(Back To Menu)

---

Vegetable Crops

No New Diseases

(Back To Menu)

---

Specialty Crops

No New Diseases

(Back To Menu)

---

Miscellaneous

No New Entries

(Back To Menu)

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Compiled by Brian Hudelson and Dante Tauscheck

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from March 14, 2026 through March 20, 2026.

 

 

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Broad-Leafed Woody Ornamentals

Plant:  Hawthorn
Disease/Disorder:  Cedar-Quince Rust
Pathogen:  Gymnosporangium clavipes
County:  Waukesha

(Back To Menu)

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Field Crops

No New Diseases

(Back To Menu)

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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:  Begonia
Disease/Disorder:  Bacterial Blight
Pathogen:  Xanthomonas sp.
County:  Adams

Plant:  Miscellaneous Herbaceous Annuals
Disease/Disorder:  Root/Crown Rot
Pathogen:  Rhizoctonia sp.
County:  Putnam (IN)

(Back To Menu)

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Houseplants

No New Diseases

(Back To Menu)

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Needled Woody Ornamentals

No New Diseases

(Back To Menu)

---

Vegetable Crops

No New Diseases

(Back To Menu)

---

Specialty Crops

No New Diseases

(Back To Menu)

---

Miscellaneous

No New Entries

(Back To Menu)

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