We are having a series of warm days in the last few weeks, and that made me wonder about the risk of PD for this year. As you might have heard from our colleagues Dr. Doug Pfeiffer and Dr. Chris Bergh, you can predict the risk of outbreak or Pierce's Disease (PD) by monitoring winter time temperature. When your area receive more than 3 nights (or days) with temperature below 15F (-9.4C), the risk of PD outbreak will be low. It is determined by the number of nights (or days) during the winter months, and it does not happen as three consecutive nights. Here are records of 2011 winter from Virginia Cooperative Extension's mesonet weather stations. Location Days < 15F Eastern Shore AREC, Accomack Co. 1 Tidewater AREC, Virginia Beach 1 Eastern Virginia AREC, Warsaw, Richmond Co. 3 Northern Piedmont AREC, Orange Co. 5 AHS AREC, Frederick Co. 5 Claytor Nature Study Ctr., Bedford Co. 1 ...
Grape Disease Management Tips from Mizuho Nita (Grape Pathologist at Virginia Tech)