Blightline June 26
No late blight has been reported in our region. Late blight has been reported in potatoes in Adams County, WI. The genotype has not yet been identified. Late blight severity values are accumulating due to the wet and cool conditions in June. Several irrigated locations have reached late blight severity values of 15, including Beach, Inkster, Leonard, Linton, Michigan and Oakes. At this threshold value, accumulated conditions are conducive for late blight if inoculum is present; growers are encouraged to apply a protective fungicide such as chlorothalonil or mancozeb. Chlorothalonil is in short supply this year and may be difficult to find.
Blightline June 26, 2015 (pdf)