It looks like the first set of thunderstorm is coming very soon.  (Actually, I see rain drops now.)  I hope it won’t stay very long.  There are 30-40% chance of thunderstorm tomorrow too.

I received several questions about the risk of downy mildew (DM) based on the previous rain which was a risk event for DM.  Most of questions were about whether to apply a kick-back (curative) activity fungicide such as Ridomil or Prophyt.  At this time of the year, it would be a good idea to consider a kick-back material, if you: 1) did not protect your vines, say, the previous application of DM fungicide was more than 10-14 days ago, 2) had considerable rains since the last application, and 3) had an outbreak of DM in recent years.  In the other words, it is probably not necessary, if you have protected your vines, and/or you haven’t have a big out break of downy mildew in recent years.   It will take about 10 days for DM fungus to develop symptoms.  Please scout your vineyards during next week.

For your information, I rated my field trial last week and I did not see any downy mildew on our non-treated vines, but once again, it is too early to tell the effect of the rains we had this week.  Our vines are about 25-30% bloom as of today.