UW Madison/ Extension Plant Disease Diagnostic Clinic (PDDC) Update

Brian Hudelson, Sean Toporek, Ann Joy and Joyce Wu

The PDDC receives samples of many plant and soil samples from around the state. The following diseases/disorders have been identified at the PDDC from July 18, 2015 through July 24 2015.

Plant/Sample Type, Disease/Disorder, Pathogen, County

Field Crops
Soybean, Potassium Deficiency, none, Sauk

Fruit Crops
Apple, Black Rot, Sphaeropsis sp., Oneida
Apple, Cedar Apple RustGymnosporangium juniperi-virginianae, Iowa
Apple, Fire BlightErwinia amylovora, Oneida
Apple, Root/Crown Rot, Phytophthora sp., Pythium sp, Kenosha, Sawyer
Cranberry, Tobacco Streak, Tobacco Streak Virus, Monroe
Cherry, Cheery Leaf Spot, Blumeriella jaapii, Rock
GrapeBlack Rot, Phyllosticta ampelicida, Dane, Polk
Honeyberry, Powdery MildewMicrosphaera sp., Dane
Strawberry, Angular Leaf Spot, Xanthomonas fragariae, Iowa
Strawberry, Root/Crown RotFusarium sp., Iowa

Vegetables
Onion, Downy MildewPeronospora destructor, Rock
Onion, Purple Blotch, Alternaria porri, Rock
Onion, Stemphylium Leaf Blight, Stemphylium sp, Rock, Columbia
Potato, Early BlightAlternaria solani, Portage
Snap Beans, Ashy Stem Blight, Macrophomina phaseolina, Waushara
Snap Beans, Root/Crown RotFusarium spp., Waushara
Soybean (Edible), Root/Crown RotFusarium sp., Chippewa
Soybean (Edible), Target Spot, Corynespora cassiicola, Chippewa
Tomato, Catfacing, none, Iowa
Tomato, Cucumber Mosaic, Cucumber Mosaic Virus, Iowa, Grant, Winnebago
Tomato, Septoria Leaf Spot, Septoria lycopersici, Iowa, Portage
Tomato, Tobacco Mosaic, Tobacco Mosaic Virus, Iowa, Grant, St. Croix, Winnebago
Tomato, Tomato Spotted Wilt, Tomato Spotted Wilt Virus, Grant, St. Croix

Soil
Alfalfa SoilAphanomyces Seedling Blight, Aphanomyces euteiches race 2, Houston (MN)
Alfalfa Soil, Phytophthora Seeding Blight, Phytophthora medicaginis, Houston (MN)

For additional information on plant diseases and their control, visit the PDDC website at pddc.wisc.edu