Preventing MILDEW

摘要

Target sprays during the plant's most susceptible time: from prebloom to four weeks after fruit set. Onee you see a problem with powdery mildew in your vineyard, you're already too late. Washington State University extension specialists want grape growers to focus on prevention, rather than wait for symptoms to trigger their action. Most pest management programs use economic thresholds to guide action or spray decisions, but disease management programs typically don't fit the economic threshold concept, says WSU's Dr. Michelle Moyer, statewide viticulture extension specialist. The economic threshold, also called the treatment or action threshold, is a predetermined pest density/population level at which control is needed to prevent the pest from reaching an economic injury level.