Boy, it has been a rainy month of September! If you are subscribing to Mark Chien's "Wine Grape Information from Penn State", you probably seen this, but here's a link to NOAA on the precipitation record from Irene and Lee . It gives you an idea of how we started this month with a lot of moisture in the air. As you can imagine, this type of weather will increase risks of having late season rots. I have heard some people had an outbreak of Botrytis, sour rot, ripe rot, etc. The pictures above are examples of Botrytis bunch rot. The management strategies for these rots are discussed in the previous post . Since temperature during these rain events were low and we have not have many days with sunlight, you may want to keep your clusters hanging little longer. Please keep remind yourself about the PHI when you decide to apply fungicides. One of the strategies for sour rot and Botrytis management discussed was the management of birds....
Grape Disease Management Tips from Mizuho Nita (Grape Pathologist at Virginia Tech)