Here are snapshots from the last two weeks (sorry for missing last week. I was busy with the VVA meeting.), showing the number of days with the risk of each disease: Ph = Phomopsis, PW = Powdery mildew, BR = Black rot, and DM = Downy mildew. N/A means there is no data or some issues with the NEWA. This year, we have been using a different downy mildew model due to inconsistency with the NEWA model. This model uses the past five days of weather to estimate spore production and the next seven-day forecast to estimate the infection risk.
Due to relatively low mean temperature and humidity during the nighttime, risks of downy mildew have been low in the past month or so. However at the VVA meeting, several growers mentioned to me that they saw powdery mildew. Please see the post-bloom grape disease management slides here.
Speaking of the VVA, here are my slides from the meeting.
I’d be interested in knowing what the current Japanese Beetle Risk is in Virginia. In most year’s past, I’ve seen significant Japanese Beetles on my grape leaves by now. However, to date I’ve only seen a few beetles here and there thruout the vineyard…..not enough to put a spray down.
However, perhaps a preventative spray may be a good idea? I’d like to hear what Mizuho and team feel about a preventive spray.