05/22/06 Columbia Basin late blight forecast

Washington Ag May 22, 2006 Potato late blight is expected in the Columbia Basin this year but the probability of occurrence is less than what it has been since the very early 1990s. Dennis Johnson of Washington State University says that's because of the low level of rainfall in April and early May, which is a key factor in the Columbia Basin Late Blight Forecasting Model. Johnson: "We are not calling for any fungicides at row closure this year like we usually do unless it rains. If it rains an application should be made at row closure and then seven days later. If it doesn't rain in the next two weeks we do not recommend a fungicide application at this time." Johnson emphasizes that the situation can change quickly so it is important to monitor fields closely and regularly for late blight. He also says it is extremely important this year to manage volunteers, especially in fields where late blight was present last year or the year before. Johnson: "If we get late blight this year it will likely come from volunteers in fields that were infected with potatoes last year or the year before." The Washington Late Blight Hotline is 1-800-984-7400. I'm Bob Hoff.