Wisconsin Late Blight Update
Updates provided by Amanda J. Gevens, Chair, Associate Professor & Extension Specialist, UW-Madison, Dept. of Plant Pathology and Yi Wang, Assistant Professor & Extension Potato and Vegetable Production Specialist, UW-Madison, Dept. of Horticulture
September 15, 2020
This afternoon, late blight was confirmed on a tomato plant from a home garden in St. Croix County, WI. This county is on the western edge of our state, just north of Pierce County (where late blight was previously confirmed on Aug 20). This disease was suspected on Fri Sep 11, but was just confirmed in our Plant Disease Diagnostic Clinic today. We will be working through the clonal lineage typing this week.
Past late blight findings in WI this season have been confined to individual sites in Adams Co. (potato US-23) and Pierce Co. (tomato Aug 20).