Powdery Mildew Treatment

As vineyard owners (and managers), we have been having another wild ride through a challenging growth year.  Early bud break, a relatively cool spring, a lot of cloudy days, and some occasional rain have all added up to ongoing war with Powdery Mildew.  I tip my hat to those of you who were proactive with treating your vines early and continuing to spray on a frequent and regular schedule.  I would expect you to be in pretty good shape.  Nevertheless, there are many vineyards that were treated frequently, but still suffered from a persistent Mildew that just does not want to be beaten.  Every week has presented a new battle, and some may have even lost the war, I’m sorry to say.  

On a happy note, a few of the vineyards that I have been managing did seemingly lose the war with Powdery Mildew, but I’m please to report that we were able to employ the use of an atomic-bomb technique to all but remove the mildew…a bomb in the form of “mid-season hard pruning.”  While the vines were seemingly decimated by the Mildew, we pruned away all heavily infected fruit, canes, and shoots…in favor of the health of the plant pushing out new growth, and potentially forming new fruit.  So far, our efforts have shown nice success.  After only a week after the hard pruning, the vines were already popping new buds and sending up new shoots.  Thanks to our SoCal long growing season, these vineyard owners will still likely enjoy a harvest…albeit late season.

Anyway, now that the days have gotten hotter, the formation of mildew will slow down a bit.  While the heat does not kill the mildew, it does slow its growth.  Of course, as the day cools and the days turn to night, the mildew continues its nasty proliferation.  But not as heavily as earlier in the season.  The good news is, the fruit is not susceptible to Mildew damage once the fruit has gone into “veraison“…the time of changing color, denoting ripening…or as some call it…sugaring up.  Until that happens, we must continue to be vigilant by fighting off the mildew with regular treatments.  The NEEM oil that I continue to recommend does not harm the fruit or its development, and can be used right up until harvest…although that should not be entirely necessary.  Finally, if your vines have suffered a lot from mildew or other problems, don’t hesitate to give them a shot of MiracleGro, either through the roots or as a foliar spray.  They will appreciate the perk-me-up.