Thunderstorms went through yesterday in Winchester area; however, air was dry (RH<80% even during the rain), and the sun came up soon after that, thus, leaves were probably dry soon after the rain. It was probably not a disease risk event. We are expecting to see more rain this afternoon.
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
Birds damage is also starting to occur.
ReplyDeleteThat's a good reminder! Bird damages can end up with Botrytis and other late season rot.
ReplyDeleteI would love to see more images of your grapevines throughout the process, just to compare mine with :)
ReplyDeleteHi Andrew,
ReplyDeleteI think that's a good idea. I will try to put as much pictures as possible!