Virginia Grape Disease Updates

Our reds broke buds, and whites have about 1-inch shoot growth on it today, and more rains in the weather forecast. It is time to think about Phomopsis! What happen from this point to pre-bloom is a relatively simple spray program to manage Phomopsis, downy mildew, and powdery mildew. During the early part of the season, I typically recommend a mix of mancozeb and sulfur or copper by itself. The reason why I recommend mancozeb now is because it works on so many different diseases (including Phomopsis which is the main target for us), plus, mancozeb has a 66-day PHI and a limit on the amount of mancozeb to be used in a year (e.g., 24 lb (or 18 lb of a.i) if you Dithane DF). Thus, I would like to use mancozeb-based product early in the season. I have been often asked whether you should include sulfur or not. If your vineyard has a history of powdery mildew outbreak, it would be a good idea to have a sulfur in your tank mix, even at early part of the season. Although you may not abl

It looks like the 2017 season for us has officially begun. Our 8 years old Chardonnay at Virginia Tech's Winchester AREC was about 10% bud break as of yesterday. Despite a warm winter, a colder spring might have kept things slow (I am not complaining!) Once again, the important disease at this point is Phomopsis cane and leaf spot. Please refer to my previous post about Phomopsis management. Also for our Chardonnay plot, we have a chronic issue with climbing cutworms. Since we know the location of our vineyard where we always see some damages, we typically apply an insecticide to the panels of vines that is facing a wooded area. Without spraying the whole vineyard, it seems to provide adequate control. Good luck with the 2017 season. I will post key disease management tips as the season moves along.

Our Chardonnay and some of the hybrid vines are in bud swell stage as of this week, and others are tagging along.  It looks like we will see bud break very soon with warmer temperature coming up next week. One of the diseases you need to consider this time of the year is   Phomopsis cane and leaf spot .  It causes minor leaf spots, which is more obvious to our eyes, but the more important damage is caused by necrotic lesions on shoots and rachis. It also causes berry rot; however, it is not common with wine grapes because of our spray programs. Materials for black rot and downy mildew are often effective against Phomopsis. Thus, the fungicide coverage for these diseases is also working as management of Phomopsis, especially later in the spring and early summer. Some cultivars, such as Viognier and Seyval Blanc, are more susceptible to Phomopsis than the others. Phomopsis takes a while to establish in the vineyard. It may take 5-6 years for Phomopsis to become noticeable if you

It was very nice to see you all at the Weekend Warrior Grape IPM workshop. I think we had a very good time with lots of discussions. Hopefully to see you at other meetings. Here is a list of materials that we covered during the meeting. Prioritization in vineyards (Tremain Hatch) VCE overview (Mark Sutphin) Grape weed management (Tremain Hatch on behalf of Dr. Jeff Derr) Interactive grape disease management (Mizuho Nita) Fungicide application template (will open a Google Drive spreadsheet, in order to save, click "file" and select "download as..." Please remember that this one is just an example. You need to come up with your own!) Please note that there is another version, under "Resources" on the right-hand side of this blog. It is in a different format, but essentially the same type of tool. Template used in the exercise (pdf) List of chemical with FRAC codes  (pdf)