It seems that we have more rains on the horizon. I hope you had a chance to protect your vines, it it was not done recently. At Winchester area, yesterday's rain events were sporadic and it was not significant disease event except for downy mildew, but some of nearby area probably had more continuous rains, thus you need to check your local weather. We have having 13 consecutive nights that favors downy mildew sporulation, thus even though the threat on fruits are gone, you may want to consider downy mildew materials to protect your foliages.
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...
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