It seems that the line of rain has passed around Winchester area (Folks around Richmond may see more rain later today). It started around 7 am and lasted until 11 am or so. The relative humidity was high (>90%) until 11:40 am. Thus, this event probably accounted for 4.7 hours of wetness (0.06 inches) and average temperature during the event was 52 F. It was little too cold and too short for Phomopsis or Black rot to develop. Please check your local weather for more information. You can click on the link on the upper right and then type in your zip code to see the record from the nearby weather station.
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.