Virginia Grape Disease Updates

2010 January - February issue of Viticulture Notes is published. There is a section of grape pathology too. Viticulture Notes and other seasonal information is distributed from our viticulturist Dr. Tony Wolf through the email. If you have not been subscribing to Tony's email list, please let me know so that we can add your name to the list. Since out website is in the process of renovation, this issue of Viticulture Notes has not been uploaded yet. In the mean time, I uploaded here for your convenience . I just came back from a meeting in Tennessee where I was invited to give talks about grape disease management ( Tennessee Horticultural Expo ). I had a good time meeting with new people. Tennessee's wine industry is smaller than that of ours, but it's growing strong. I hope we can continue communicating each other because we share similar growing conditions, especially in the southern VA and eastern TN.

VT is working on updating webpages and now our AREC pages has been changed. My new grape pathology page is here (Please click the link). It does not have many information as it did with the previous page, but it will. I will keep this blog because it is more convenient for me. Also, due to the change in URL, many of documents I linked last year is gone. I have restored some of important links, but if the file you are interested in is missing, please let me know.

Dr. Baudoin noticed that there is an error in VT's PMG on the REI for Topsin-M. If you are using Topsin-M, please read the label to confirm the Re-Entry Interval for the formulation. The REI statement for Topsin-M was somewhat confusing. In older labels, the REI was stated as 12 hours in the box of "Agricultural Use Requirements"; however, the list of individual crop stated that for grape was 7 days. The newer label of Topsin-M WSB does not state the REI in the "Agricultural Use Requirements", and now the REI for grape has been changed to 2 days . As usual, please make sure to check and follow the label.

2010 version of Virginia Tech's Pest Management Guide (PMG) is uploaded. There are many useful information on disease, insect, and weed management. Please take a look at it for your reference. As with the last year, I will prepare my version of application guide which focuses on fungal diseases. I'm planning to post it before the VVA winter meeting. If you are non-commercial (i.e., do not have the commercial pesticide applicator license), please refer to the home garden PMG . It shows management methods using non-restricted materials.

I wish you and your family a Happy New Year, and I wish this season to be a good one for everybody. Although not as much as I do during the season, I will update this blog for winter meetings and other information that I think you would be interested in. For a starter, the VVA's Winter Technical Meeting will be held in March 4-6 at Omni Charlottesville. There will be a session for grape trunk diseases that will be served as an update of the summer technical meeting of 2009. Also, I will show some results from my grape leaf roll disease survey and fungicide performance testings. I hope you can join the meeting.

I think this will be the last meetings for the season. One is at Koru farm in Stuart, VA (Sept. 30th - TOMORROW!). Caryl and Greg Talcott has been kind enough to host and organize the meeting. If you can make it, please do. I will talk about new fungicide and other management information. The other one is at Dinwiddie, VA (Oct 1st). Although this is titled late season meeting, I will talk mainly about "early" season disease management for next season, since most of people are probably either harvested, or harvesting their grapes. The list of speakers (at Dinwiddie): Dr. Mizuho Nita, VCE Grape Pathologist from Winchester VA , Mizuho will be cover Early Season Management of Grape Diseases. Dr. Paul Semtner, VCE Entomologist form Blackstone VA , Paul will cover Early Season Insect Control Methods. Janet Spencer, VCE SE Area Vegetable Extension Agent in Suffolk VA , Janet will cover General Production Tips Mike Parrish, VCE Extension Agent, Dinw...

I've been in and out of my office with my leaf roll survey project, and it has been bit difficult to frequently update the blog. Also, at this point, not much you can do about major fungal diseases. The critical time of infection is gone. If you see downy, powdery, or black rot on your bunches, the infection probably took weeks ago, if it was not a month. Thus, I will point some key issues at this time of the year. Botrytis, downy, and other rot We had a long period of wet and cool nights during the last half of August. This conditions favors both Botrytis and Downy mildew sporulation, and potential infection on nearby leaves. (i.e., it won't spready quicky, but it probably enough to increase number of spores.) If it is followed by rain (like we had last week), the risks of Botrytis and downy mildew increase. As I mentioned earlier, downy mildew won't touch berries at this point. Berries are resistant to the infection. However, with a prolonged rain or high hu...