Critical Alert for Potato Farmers: Managing Late Blight in Michigan
Late blight, a devastating disease for potato crops, has been confirmed in a commercial field in St. Joseph County, Michigan, according to a report by Dr. Amanda Gevens from the University of Wisconsin-Madison. The confirmation of the Phytophthora infestans pathogen, genotype US-23, underscores the need for immediate and enhanced disease management strategies for potato farmers in the region.
Details of the Outbreak
The late blight was identified on July 23, 2024, in a small section of approximately five square feet in a commercial field located on the southwestern edge of St. Joseph County, bordering Indiana. Rob Schafer of Mid-Michigan Agronomy promptly worked on the diagnostics and shared the crucial information, enabling local producers to take swift action to mitigate the spread of this pathogen.
Recommended Management Practices
For managing the US-23 genotype of Phytophthora infestans, phenylamide fungicides, including mefenoxam and metalaxyl, are typically effective. Farmers are advised to implement preventative foliar programs and maintain diligent crop monitoring to prevent further spread. The current risk for late blight in Michigan ranges from low to medium, but certain areas have experienced conditions conducive to the disease due to frequent and heavy rain events in recent weeks.
Monitoring and Forecasting
Late blight forecasting for the Upper Midwest can be accessed through the UW-Madison Vegetable Disease & Insect Forecasting Network, which provides valuable insights into the risk levels and helps farmers take proactive measures. The link to the forecasting model is: UW-Madison Vegetable Disease & Insect Forecasting Network.
Despite early reports in July of late blight in Kent and Elgin counties in Ontario, Canada, no further regional detections have been documented. Ongoing monitoring efforts by the MSU Potato and Sugar Beet Pathology program have not detected Phytophthora infestans DNA in spore samplers currently deployed in research and commercial fields in Montcalm County.
Conclusion
The confirmation of late blight in St. Joseph County serves as a critical reminder for potato farmers to remain vigilant and proactive in their disease management practices. By utilizing effective fungicides, monitoring crop conditions, and leveraging forecasting tools, farmers can protect their crops and sustain productivity.
