Here are snapshots 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. N/A means there is no data or some issues with the NEWA (which has been reported).

It seems like many of us received much-needed moisture. However, this also meant that the environmental conditions posed risks of diseases. Among the locations listed above, Northern VA and Southwestern VA had several days of downy mildew risk events in the past two weeks, and had more than four days (out of seven) of infection risk days in the past week. If your vines are not adequately protected, it would be a good idea to use some reach-back materials (e.g., a phos acid such as Prophyt and Agri-Fos, or one of Ridomil products) for downy mildew management. If you are in such a situation, do not wait until you see downy mildew. These materials work when infection is happening, but not after the pathogen has established and produced the next round of spores (i.e., they do not work after we see downy mildew).

For the detailed recommendations, please check our pest management guides, the previous post about at bloom protection, and today’s slides (below).