Compiled by Brian Hudelson and Hulubanche Kassa

The following diseases/disorders were identified at the Plant Disease Diagnostics Clinic from May 30, 2026 through June 5, 2026.

Broad-Leafed Woody Ornamentals

Plant:  Aspen (Quaking)
Disease/Disorder:  Venturia Leaf Spot/Blight
Pathogen:  Venturia morelettii
County:  Green Lake

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

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

Plant:  Buckthorn (Common)
Disease/Disorder:  Fusarium Canker
Pathogen:  Fusarium sp.
County:  Rock

Plant:  Buckthorn (Common)
Disease/Disorder:  Shoot Blight
Pathogen:  Asteromella sp. (Suspected)
County:  Rock

Plant:  Buckthorn (Common)
Disease/Disorder:  Tubercularia Canker
Pathogen:  Tubercularia sp.
County:  Rock

Plant:  Hibiscus
Disease/Disorder:  Herbicide Damage
Pathogen:  None
County:  Boone (IL)

Plant:  Hickory (Shagbark)
Disease/Disorder:  Diplodia Canker
Pathogen:  Diplodia sp.
County:  Dane

Plant:  Holly
Disease/Disorder:  Cytospora Canker
Pathogen:  Cytospora sp.
County:  Milwaukee

Plant:  Holly
Disease/Disorder:  Diplodia Canker
Pathogen:  Diplodia sp.
County:  Milwaukee

Plant:  Hydrangea
Disease/Disorder:  Herbicide Damage
Pathogen:  None
County:  Boone (IL)

Plant:  Maple (Korean)
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  Dane

Plant:  Maple (Red)
Disease/Disorder:  Sphaeropsis Canker
Pathogen:  Sphaeropsis sp.
County:  Dane

Plant:  Maple (Sugar)
Disease/Disorder:  Anthracnose
Pathogen:  Discula sp.
County:  Waukesha

Plant:  Maple (Unspecified)
Disease/Disorder:  Anthracnose (Suspected)
Pathogen:  Discula sp.
County:  Waukesha

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

Plant:  Tree (Unspecified)
Disease/Disorder:  Anthracnose
Pathogens:  Gloeosporium 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

Plant:  Blueberry
Disease/Disorder:  Winter Injury (Suspected)
Pathogen:  None
County:  Jefferson

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Herbaceous Ornamentals

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

Plant:  Prairie Smoke
Disease/Disorder:  Damping-Off
Pathogens:  Pythium sp., Rhizoctonia sp.
County:  Rock

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Houseplants

No New Diseases

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Needled Woody Ornamentals

Plant:  Arborvitae
Disease/Disorder:  Winter Burn (Suspected)
Pathogen:  None
Counties:  Dane, Walworth

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

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

Plant:  Juniper
Disease/Disorder:  Kabatiella Tip Blight
Pathogen:  Kabatiella sp.
Counties:  Dane, Waukesha

Plant:  Pine (Limber)
Disease/Disorder:  Root/Crown Rot
Pathogen:  Phytophthora sp.
County:  Dane

Plant:  Pine (Unspecified)
Disease/Disorder:  Phomopsis Canker
Pathogen:  Phomopsis sp.
County:  La Crosse

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Vegetable Crops

Plant:  Potato
Disease/Disorder:  Leaf Blight
Pathogen:  Phytophthora nicotianae
County:  Unknown (MO)

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

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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 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

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Field Crops

No New Diseases

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Forage Crops

No New Diseases

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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

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Herbaceous Ornamentals

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

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Houseplants

No New Diseases

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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

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Vegetable Crops

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

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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 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

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Field Crops

No New Diseases

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Forage Crops

No New Diseases

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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

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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

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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 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

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Field Crops

No New Diseases

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Forage Crops

No New Diseases

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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

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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 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

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Field Crops

No New Diseases

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Forage Crops

No New Diseases

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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

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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

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Miscellaneous

No New Entries

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