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Rains forecasted for this weekend.

It seems that we will have a rainy weekend.  Chances of rain are around 40-60% throughout the state.  Forecasted temperature during the hours with a high chance of rain is around mid-50's to low-60's.  This may become our first real risk of disease development.  (Of course, since I stated that, we may not get rains.)

If you have sprayed in preparation to the previous rains (i.e, within 10 days or so), then your vines are probably protected.  It also depends on how much your vines have been grown and how much rainfall you have received.  At Winchester, many of the rain events were showers with less than 0.02 inches of precipitation, and due to more like a normal weather, shoots were not growing as vigorously as they did few weeks ago.  Please check your record, vines, and local weather history.

However, if you were waiting until now and your vines are grown considerably, then you may want to protect your vines, simply because there are three days of rain forecasted and temperature range could be high.  You can always wait until tomorrow or even Saturday morning to make a decision, but I just want to give you a heads-up.  The target diseases are Phomopsis and black rot, and maybe downy mildew.  Mancozeb products will provide a good to excellent protection against these diseases.  If you prefer using other materials, make sure that the product has an efficacy against all three.  I think it is still too early in the season to talk about powdery mildew, but adding a low rate of sulfur is always a good (and cheap) insurance.  For rates and list of materials, please refer to PMG or my spray guide that you can find in the links on the right.
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