Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from May 23, 2026 through May 29, 2026.

Broad-Leafed Woody Ornamentals

Plant:  Boxwood
Disease/Disorder:  Cold Injury (Suspected)
Pathogen:  None
County:  Milwaukee

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

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

Plant:  Ironwood
Disease/Disorder:  Leaf Blister (Suspected)
Pathogen:  Taphrina virginica
County:  Milwaukee

Plant:  Lilac
Disease/Disorder:  Bacterial Blight
Pathogen:  Pseudomonas syringae pv. syringae
County:  Dane

Plant:  Maple (Norway)
Disease/Disorder:  Root/Crown Rot
Pathogens:  Phytophthora sp., Cylindrocarpon sp.
County:  Racine

Plant:  Maple (Red)
Disease/Disorder:  Anthracnose
Pathogen:  Discula sp.
County:  Green

Plant:  Maple (Red)
Disease/Disorder:  Cold Injury (Suspected)
Pathogen:  None
County:  Green

Plant:  Maple (Red)
Disease/Disorder:  Root/Crown Rot
Pathogen:  Phytophthora sp.
County:  Waukesha

Plant:  Maple (Red)
Disease/Disorder:  Verticillium Wilt
Pathogen:  Verticillium sp.
County:  Waukesha

Plant:  Oak (Unspecified)
Disease/Disorder:  Herbicide Damage
Pathogens:  None
County:  Monroe

(Back To Menu)

Field Crops

No New Diseases

(Back To Menu)

Forage Crops

No New Diseases

(Back To Menu)

Fruit Crops

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

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

Plant:  Apple 
Disease/Disorder:  Cold Injury (Suspected)
Pathogen:  None
County:  Dane

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

(Back To Menu)

Herbaceous Ornamentals

Plant:  Peony
Disease/Disorder:  Xanthomonas Blight
Pathogens:  Xanthomonas sp.
County:  Dane

(Back To Menu)

Houseplants

No New Diseases

(Back To Menu)

Needled Woody Ornamentals

Plant:  Arborvitae
Disease/Disorder:  Winter Burn (Suspected)
Pathogens:  None
County:  Waukesha

Plant:  Fir (Unspecified)
Disease/Disorder:  Gelatinosporium Canker
Pathogen:  Gelatinosporium sp.
County:  Dane

Plant:  Spruce (Unspecified)
Disease/Disorder:  Root/Crown Rot
Pathogen:  Pythium sp.
County:  La Crosse

(Back To Menu)

Vegetable Crops

Plant:  Potato
Disease/Disorder:  Black Leg
Pathogens:  Dickeya dianthicola, Pectobacterium sp.
County:  Waushara

(Back To Menu)

Specialty Crops

No New Diseases

(Back To Menu)

Miscellaneous

No New Entries

(Back To Menu)

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.

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

(Back To Menu)

Field Crops

No New Diseases

(Back To Menu)

Forage Crops

No New Diseases

(Back To Menu)

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

(Back To Menu)

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

(Back To Menu)

Houseplants

No New Diseases

(Back To Menu)

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

(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)

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.

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

(Back To Menu)

Field Crops

No New Diseases

(Back To Menu)

Forage Crops

No New Diseases

(Back To Menu)

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

(Back To Menu)

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

(Back To Menu)

Houseplants

No New Diseases

(Back To Menu)

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

(Back To Menu)

Vegetable Crops

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

(Back To Menu)

Specialty Crops

No New Diseases

(Back To Menu)

Miscellaneous

No New Entries

(Back To Menu)

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.

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

(Back To Menu)

Field Crops

No New Diseases

(Back To Menu)

Forage Crops

No New Diseases

(Back To Menu)

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

(Back To Menu)

Herbaceous Ornamentals

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

(Back To Menu)

Houseplants

No New Diseases

(Back To Menu)

Needled Woody Ornamentals

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

(Back To Menu)

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

(Back To Menu)

Specialty Crops

No New Diseases

(Back To Menu)

Miscellaneous

No New Entries

(Back To Menu)

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.

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

(Back To Menu)

Field Crops

No New Diseases

(Back To Menu)

Forage Crops

No New Diseases

(Back To Menu)

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

(Back To Menu)

Herbaceous Ornamentals

No New Diseases

(Back To Menu)

Houseplants

No New Diseases

(Back To Menu)

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

(Back To Menu)

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

(Back To Menu)

Specialty Crops

No New Diseases

(Back To Menu)

Miscellaneous

No New Entries

(Back To Menu)

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.

Broad-Leafed Woody Ornamentals

No New Diseases

(Back To Menu)

Field Crops

No New Diseases

(Back To Menu)

Forage Crops

No New Diseases

(Back To Menu)

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

(Back To Menu)

Herbaceous Ornamentals

No New Diseases

(Back To Menu)

Houseplants

No New Diseases

(Back To Menu)

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

(Back To Menu)

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

(Back To Menu)

Specialty Crops

No New Diseases

(Back To Menu)

Miscellaneous

No New Entries

(Back To Menu)

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.

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

(Back To Menu)

Field Crops

No New Diseases

(Back To Menu)

Forage Crops

No New Diseases

(Back To Menu)

Fruit Crops

No New Diseases

(Back To Menu)

Herbaceous Ornamentals

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

(Back To Menu)

Houseplants

No New Diseases

(Back To Menu)

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)

Vegetable Crops

No New Diseases

(Back To Menu)

Specialty Crops

No New Diseases

(Back To Menu)

Miscellaneous

No New Entries

(Back To Menu)

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.

Broad-Leafed Woody Ornamentals

No New Diseases

(Back To Menu)

Field Crops

No New Diseases

(Back To Menu)

Forage Crops

No New Diseases

(Back To Menu)

Fruit Crops

No New Diseases

(Back To Menu)

Herbaceous Ornamentals

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

(Back To Menu)

Houseplants

No New Diseases

(Back To Menu)

Needled Woody Ornamentals

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

(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)

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.

Broad-Leafed Woody Ornamentals

No New Diseases

(Back To Menu)

Field Crops

No New Diseases

(Back To Menu)

Forage Crops

No New Diseases

(Back To Menu)

Fruit Crops

No New Diseases

(Back To Menu)

Herbaceous Ornamentals

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

(Back To Menu)

Houseplants

No New Diseases

(Back To Menu)

Needled Woody Ornamentals

No New Diseases

(Back To Menu)

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

(Back To Menu)

Specialty Crops

No New Diseases

(Back To Menu)

Miscellaneous

No New Entries

(Back To Menu)