Tuesday, August 26, 2014

Last stretch spray consideration

Due to the rain event over the weekend, many people are concerned about protection for next week or two before the harvest.  At this point, the tools are rather limited due to PHI as well as wine making consideration.

For downy mildew (especially for foliage, your berries are protected at this point), you can use Phosphonate (= phosphorous acid) product or captan.  (Both have 0-day PHI)

For late season rots, especially Botrytis, you can use captan, Elevate (both have 0-day PHI), Switch (7-day PHI), Rovral (7-day PHI), Scala (7-day PHI), Vanguard (7-day PHI), or maybe Endura, Pristine or Luna products (these three have 14-day PHI).

For ripe rot and bitter rot, a QoI (Abound, Pristine, Sovran, Flint, etc = 14-day PHI) and captan seem to be the key product.  Our lab is investigating the efficacy of a phosphonate too.

As usual, please consider the situation at your vineyard as well as weather forecast.  If you do not see any issues at your place, picking in 7-day, and don't see any rain in the forecast, you may not need to spray for downy or Botrytis.  (You may want to have something for powdery mildew for foliage, though)

Often time, wine makers do not like to see a certain products close to the harvest (e.g., captan, copper, sulfur), thus, make sure to have a good communication with your wine maker (but when it comes down, having a crop is more important than not having it, though).

Also, make sure to keep vines as happy as possible after harvest too.  They will need time to store carbohydrate into their trunk for winter survival.

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