Virginia Grape Disease Updates

I think many of you are either harvesting or getting ready for it.  We harvested our Chardonnay and Merlot yesterday. (Of course most of them are damaged due to our fungicide trial, but there are a few left...) It seems like we are expecting some rain over this weekend.  The question is what to do in terms of the last minute disease management.  If you have clean vineyard without major rot issues, and you only have only a few days to go, you probably not need to take action.  If you have clean vineyard, but you still have more than 10 days to go, it may depends on the condition of the berries.  If you notice any wounding on berries (by birds, hornets, sun damage, etc), then you may want to consider captan before this rain because many of late season rots take advantage of these wounds.  If you have nice clean berries, then, you may able to wait and see. If you have some rot issues, again captan is a nice tool.  It is effective against variety of pathogens, and it has a very

After yesterday's post, Winchester area received measurable rain.  ;)  The estimated wetness duration was 14 hours with 72F.  It was long and warm enough for Botrytis and Downy mildew.   It looks like we are expecting a few more rain events in next few days due to the effect of a tropical depression Issac.  We will see...

We are having a very humid day today in Winchester area.  There have been several rains passed since early morning, but only a few of them were enough to be recorded at weather station (it need to be more than 0.25 cm/0.01 inches).  Plus, even though the RH has been high, it was not higher than 70% in most of the day.  Thus, if anything, there were a low risk for downy mildew infection event. I imagine many of you are preparing for harvesting now.  I am hoping not seeing too many rains!