Grape Disease Risks: 7/29 – 8/5/2026

NEWA is an Agricultural Weather Station Network, and we are part of the team. Here is a snapshot from last week showing the number of days with risk for each disease: Ph = Phomopsis, PW = Powdery mildew, BR = Black rot, and DM = Downy mildew. N/A means there is no data or issues with the NEWA. I am waiting to hear back from the weather station company about fixing the one in Stafford. Note: Since we are out of the critical period for black rot and Phomopsis, you can ignore them. Note 2: I moved some stations with data transmission issues.

There were more than four of eight days with a risk of downy mildew infection in many locations in central to south VA. As we discussed in the previous virtual vineyard meetings, we still need to maintain our vines to ensure healthy canopies that support bud formation for next year, cane or spur selection, and winter survival. Speaking of the meeting, our next monthly Virtual Viticulture meeting is scheduled for this Thursday (8/6) at 1 PM. Please join us!

For detailed recommendations, please refer to last week’s posting.

Downy mildew forecast

Please click the table above to enlarge. Central VA locations show high probabilities of downy mildew in the upcoming week, most likely reflecting inoculum buildup based on last week’s weather. I hope you can find a time to protect your vines before these events.

The downy mildew forecasting effort is supported by the Virginia Wine Board.