Late blight has been found in two additional counties (Wyoming and Columbia) in New York, and in eight counties in Pennsylvania. It’s also been reported in two counties in Maine. See a map of late blight reports on usablight.org. Most isolates have been identified as US-23, which is sensitive to mefenoxam, the active ingredient in Ridomil, however US-24 has also been identified in Wyoming and Erie counties in New York. US-24 is classified as intermediate in its sensitivity to mefenoxam, so it’s very important for conventional farmers to have their late blight isolate identified to choose the most effective fungicide. Instructions for submitting samples to the Fry lab at Cornell can be found on the usablight.org web site. And if you haven’t already, sign up for text or email alerts from usablight.org.
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