Earlier than usual fungicide application recommended for potato late blight this year

Washington Ag Today May 27, 2011 The potato late blight forecasting model is predicting that late blight will be a severe problem in the Columbia Basin this year if growers do not take adequate control measures. Washington State University plant pathologist Dennis Johnson says the probability that late blight will be a problem is greater than 95%.

Johnson: “And we are expecting cool, wet weather in the next two weeks. Cooler weather than normal and that will favor the development of late blight.”

The usual recommendation to control late blight is for growers to apply a fungicide at row closure, but Johnson says that has changed this year.

Johnson: “Because of the increased threat we are recommending that they begin about a week, seven to ten days before row closure. That would be projected row closure since they don‘t know exactly when it will be, but they do have a pretty good idea from watching their crop and from previous years.”

Johnson says Washington potato growers have a pretty good memory about past epidemics of late blight.

Johnson; “And they realize that if this disease gets in front of them that they are not going to win. If you give late blight a running start you will never beat it.”

Keep up to date with the Late Blight Hotline at 1-800-984-7400.

That’s Washington Ag Today. Brought to you in part by the Washington State Potato Commission. Nutrition today. Good health tomorrow. I’m Bob Hoff on Northwest Aginfo Net.