Now the season is wrapping up, and one of questions I get often is “when to spray what to protect your crop at the last stretch”. Unfortunately (as with everything else), my answer to the question is “it depends.” But it won’t help anybody, so, let’s go over several potential scenarios and see one of them makes sense to you. Case 1: you are expecting harvest in 2-3 weeks I think many of Chardonnay and other early white cultivars are about to be harvested. Luckily, around Winchester area, we have had a good stretch of relatively dry weather. We had rain showers came in several times, but only two of them, one at 8/4 and another one on 8/20 were long enough to initiate major late season diseases, such as Botrytis. We have three Botrytis trials, but we have not seen evidence of Botrytis outbreak. Moreover, at Winchester area, a forecast of next rain is on next Tuesday, and it looks like a case of another thundersto...
Grape Disease Management Tips from Mizuho Nita (Grape Pathologist at Virginia Tech)