Michigan potato late blight update – July 20, 2023
Late blight was reported in Ontario, Canada on July 18, 2023.
Potato late blight was reported in Simcoe County Ontario, Canada, on July 18, 2023. Genotype testing is in progress by North Carolina State University. Michigan State University Extension will provide updates as more information becomes available. For typical foliar symptoms, see Photo 1. No other reports of late blight have been received at this time. A map of current late blight observations can be monitored at USABlight.
In Michigan, no late blight has been reported and current weather conditions indicate low to medium risk throughout the state (Photo 2). However, following potato late blight incidences in Montcalm County last year and abundant volunteer pressure noted in areas this season, careful monitoring is recommended. If left unmanaged, volunteers can serve as possible inoculum sources, especially for late blight.
Please contact MSU Potato and Sugar Beet Pathology at firstname.lastname@example.org or 517-355-3863, or MSU Plant & Pest Diagnostics at email@example.com or 517-355-4536 for disease diagnosis and management support. Visit our websites for more information.