Hello,
Please note an important disease update. Potato late blight (clonal lineage/genotype US-23) was discovered in a south-western Michigan County (St. Joseph) on August 12, 2026. Initial characterization of the pathogen was completed by Rob Schafer and his lab at Mid-Michigan Agronomy in DeWitt Michigan. Samples were also sent to Dr. Phillip Wharton at the University of Idaho Potato Pathology lab for secondary confirmation. Rob shared with his grower clients that the weather forecasted for the area over the next 5 days (temps in the 70s) is conducive for late blight development and he urged growers to be extra vigilant in scouting for this important disease.
Please see past newsletters for fungicide information and additional management strategies.
Regards
Amanda
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Amanda Gevens
Associate Chair, Professor & Extension Specialist
Administrative Director of the Wisconsin Seed Potato Certification Program
Fritz Friday Chair for Vegetable Production Research
Plant Pathology Department
1630 Linden Drive Room
University of Wisconsin-Madison
Madison, WI 53706
gevens@wisc.edu/608-575-3029
Potato & Vegetable Pathology Research and Extension
