Late Blight Strikes Again — Blame It on the Weather

This summer New Yorkers have seen more than their share of late blight, a dread disease of potatoes and tomatoes. The abundance of rain we’ve had statewide provides perfect conditions for the “water mold” pathogen that causes this disease. August alone saw 36 late blight reports in New York. Pennsylvania and the New England states have also reported many infections.

And — the growing season’s not over yet. Which means late-blight season isn’t either.

Late blight gets ugly fast, whether you grow tomatoes or potatoes. Photo courtesy Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org
Late blight gets ugly fast, whether you grow tomatoes or potatoes. Photo courtesy Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.org

How can a farmer or gardener learn where late blight is, the better to protect their crops? Check out the USAblight website.

USAblight maps late blight finds across the US. Farmers can find information on which isolates of the pathogen have been found; this helps them make the best fungicide choices to protect their crops. Gardeners can see if late blight is approaching their area and either protect their tomatoes and potatoes with fungicide or be ready to take out every infected plant — a must to avoid being part of the problem.

Learn more about how to recognize late blight by viewing videos on how to scout for late blight — or other diseases you might mistake for blight.

NYS IPM is part of the team that manages reports on USAblight.  We’re also supporting the trial of a new forecasting system that helps farmers cut down on fungicides when they’re growing disease-resistant varieties. We hope late blight hasn’t found your farm or garden yet — but if it has, study up to so you can be prepared next year.

Late blight at the micro level: pretty on the inside — but ugly on the outside,.
Late blight at the micro level: pretty on the inside — ugly on the outside. Photo courtesy R. V. James,  Cornell University.

Late blight, up close and personal: Each plant disease’s root cause? A pathogen. But pathogens have enablers. First among them is the weather. Though the weather is entirely outside our control, still — with DSS and other forecasting tools, we can do something about it.