As a part of a Wine Board-funded the Sentinel Vineyard project, we received NEWA weather stations that have been installed throughout the state. Here’s a snapshot from the last week, showing the number of days with the risk of each disease: Ph = Phomopsis, PW = Powdery mildew, BR = Black rot, and DM = Downy mildew.
Rains observed during the last week resulted in at least a day with the risk of Phomopsis infection in nearly all locations. Our Cabernet Sauvignon is right at the time for Phomopsis protection spray (~1-3 inches shoot growth), thus, many locations in the southern and central VA are probably out of period to provide protection against Phomopsis.
There were four days with downy mildew infection risk at Charles City, and two days at Tyro and Washington, indicating warm and humid nights were observed. Several days with a high risk of powdery mildew were observed at Floyd, Winchester, and Leesburg locations. Make sure to include a downy mildew material (Mancozeb or captan or fixed copper will do) and a powdery mildew material (sulfur or fixed copper is a good choice at this time of the season) in your spray materials.
The image above is just a summary. Please visit https://newa.cornell.edu/ to obtain more detailed information. You can check daily weather data as well as disease and insect pest model results including forecasted risks. We paid the annual fee so that growers in Virginia can freely access NEWA. Please take advantage of the resources.