Vineyard management June 14

By Terence Bradshaw

The near-daily rain the past week hasn’t amounted to much accumulation, so any protective fungicides applied during the narrow low-wind window of June 10-11 are likely still present on the surface of leaf tissues. However, plentiful moisture plus the warm, sunny weather on tap the next few days and grapes’ propensity for vigorous growth means that new shoot tissues will be emerging that require coverage. We have mostly left phomopsis infections behind, but powdery and downy mildew, black rot, anthracnose, and botrytis remain active concerns in the vineyard and vines should be protected again before the next expected rain (which may be a week out).

Insects are a relatively minor concern for Vermont vineyards, with a few exceptions. We are seeing a bit of grape tumid gall in the UVM vineyard this year. This is an infrequent pest that causes visually striking but relatively insignificant damage to the vines, and management practices are not recommended against them. Grape berry moth is the next insect to note in vineyards, although it likely won’t be active for another couple of weeks. Traps are available from Gemplers or Great Lakes IPM to assess flight patterns in the vineyard. Generally, one application of a narrow-spectrum material effective against lepidopteran pests such as Intrepid, Delegate, or Altacor (see other options in the 2016 New York Pennsylvania Grape IPM Guidelines), applied 10-14 days after bloom followed by another application 10-14 days after that will generally manage that pest for the season. Better management may be performed by scouting clusters and applying one of those materials or a Bt product immediately upon the first signs of larval feeding. There is also a good grape berry moth degree day model in the NEWA system that may be of use in your vineyard.