Virginia Grape Disease Updates

Due to many rain events and relatively cold weather, it looks like we are somewhat back in truck in terms of the growth stages. When shoots are about 10-12 inches long (i.e., right now), downy mildew, powdery mildew, and black rot tend to show up. Then, at bloom time, flowers and young berries will be susceptible to these diseases, and young berries are susceptible until 4-6 weeks after bloom.   In addition, Botrytis, ripe rot, and bitter rot can cause infection on flowers.   Yes, it is a lots of diseases to think about. What you need to think about is which disease(s) have been the major issues at your vineyards. The disease history of your vineyards tends to repeat itself. Downy and black rot management depend on weather condition.   I have seen cases where downy or black rot developed prior to bloom under wet conditions, and this year would be such a case, if you could not keep up with the protection. If you have concerns on downy or black rot...

Here comes 2013 version of " Workbook for Developing an Effective Fungicide Spray Program for Wine Grapes in Virginia ".   Although I finished it a few weeks ago, and used in the IPM workshop, I forgot to post it in here!  As with the previous version, it may contain some errors, so, if you find any (or if you have comments and suggestions), please let me know. You can also download our Pest Management Guide and other materials, including Excel version of the template from the workbook, from the "Resources" section on the right hand side of this blog.

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.