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Disease risks from 16 May- 18 May

The rain started around 9:20 PM on 16 May in Winchester, and since then, there were several rain and thunderstorms went through the area.  The relative humidity remained high even between the rains, and it was around 10 AM on 18 May when things were started to dry out.  Thus, it was about 38.5 hours of estimated wetness event, with 0.08 inches of rain and average temperature of 62F.  As expected, it was long and warm enough for Phomopsis, black rot, and downy mildew.

We were not affected, but some of you have experienced hails during this week's series of wet weather events.  Hopefully, it did not cause a major damage to your vines.

It seems that the chance of precipitation is low for tomorrow, Saturday, and Sunday. 

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Disease risks from yesterday's rain

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EPA is reviewing captan

Captan, which we use extensively to manage downy mildew, Phomopsis, ripe rot, and other grape diseases, is currently under review by the EPA. In order to keep captan as one of our tools to control grape diseases,  please respond to the EPA's registration review page to post your comment  (will open the EPA page). With increasing cases of fungicide resistance with newer products in our region, it is very important for the majority of commercial grape growers located east of the Rockies to keep older multi-site materials such as captan to be used as a backbone of the spray program.  Also, please forward the message to other producers and stakeholders who should respond to the need for this fungicide in our industry.