Grapevines at the UVM Horticulture Research & Education Center are showing up to three to five inches of shoot growth, depending on variety. We are beginning to enter a critical time for disease management- all growers should plan on starting your spray program this week or soon thereafter (for inland growers with less growth). I pretty-well listed the strategies to take last week, so I’ll allow folks to look there.
Now is a good time to get out and clean up the ‘nubs’ left at the ends of spurs after pruning that will die out and serve as reservoirs for phomopsis and other diseases. While you’re at it, this is an especially good time to thin shoots. Cold hardy grapes trained to a high-wire trellis and in good health can support about six shoots per foot of canopy; select the best developing shoots and break off the others now while they are easily breakable with your fingers. Maria Smith and Dr. Michela Centinari at Penn State wrote a good summary of shoot thinning available here. I suggest reading it on the deck this holiday coming weekend with a nice glass of wine, and getting out in the vineyard next week to set this year’s crop on the right track.
As a reminder, all of my older IPM bulletins are archived on the UVM Fruit Blog.
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