Please see the article in this link about the risk of 17-year cicada risks for this year. Looks like many counties east of Blue Ridge Mountains are in high risk zone. They lay eggs on branches (including grape canes), and young tender branches are more susceptible. If you have a young vineyard (1-2 years old) in the high risk zone, you may want to consider to take an action to protect your vines (grow-tubes, netting, extra shoots, etc). Please see Doug's article (about 2004 outbreak) for more details. Please consult with your local extension agents about the risk of your region.
At Winchester, we had light rain events during the night of 6/12/09, but it was short events and the relative humidity was low (80% or so), thus it probably did not promote any infections. However, we are experiencing continuing favorable nights for downy mildew sporulation (average T>55F, high RH (80-100%)) for 10 days now. Yesterday, we conducted a formal disease assessment, and observed first incidence of powdery mildew for this season. We had plenty of infection events in last two months, so it was not surprising. At this point, it is a trace level of infection on untreated vines. Downy mildew was the major disease so far. We had up to 40% incidence on untreated vines. Next runner-up was black rot. It varies vine to vine, but some of vine had 10-15% incidence. Phomopsis was omnipresent as I expected from early May rain falls, but severity was low overall. We will examine diseases again in the near future, and I will update as the season goes. Here is downy mildew ga
Comments
Post a Comment
Please leave your comment here. In order to avoid spam messages, l moderate comments, thus it may take a few hours for your comment to be posted on the page.