Michelle Moyer reminds growers who had powdery mildew problems last year to prepare for disease carryover this year. Botrytis bunch rot is a different beast than grape powdery mildew, says Dr. Michelle Moyer, Washington State University viticulture extension specialist. While it’s not a problem pathogen every year, exceptionally wet weather can trigger the disease, so Washington grape growers should consider dual-acting fungicides. A broad-spectrum fungus, the bunch rot pathogen will go after just about anything, she said. The pathogen overwinters in the vineyard on mummified berries, moldy bunches, and vineyard debris, so there’s no real way to eliminate it. “You’re […]