By Professor Paul Read, University of Nebraska Viticulture Program
The time of year that we’ve all been waiting for and working toward is either rapidly approaching or now upon us. Many Nebraska vineyard managers are looking at a good-to-great crop. Unfortunately, a few have vineyards that have been decimated or destroyed by hail or wayward herbicide drift, and to those we offer condolences with hopes for a better year in 2017. If you experienced hail damage, please see Dr. Annamiek Schilder’s excellent write-up prescribing appropriate measures to consider following a serious hail event in the August issue of VineLines coming soon.
By now most of you probably have your bird deterrents in place, including netting, but following are some other pre-harvest guidelines to consider:
- Avoid applying copper sulfur, captan or some other fungicides within 30 to 45 days of your anticipated harvest date. Sulfur and copper can cause off-tastes in wine, while captan (and possibly other fungicides) may interfere with fermentation.
- Maintain a functional canopy for long enough to fully ripen the grapes; this may require application of fungicides to control downy and/or powdery mildew.
- Scout for late-season bunch rots. Some bunch rot-prone cultivars such as ‘Vignoles’ can be particularly affected by Botrytis and other rots. Some bunch rots are especially aggressive if berries have been damaged by birds, hail insects or powdery mildew.
- Be alert to potential problems that may be caused by opportunistic insects such as multi-colored Asian lady beetles (MALB), stink bugs, spotted winged drosophila, Japanese beetles, and of course wasps such as yellow jackets. If a particularly significant infestation occurs, please alert us at the University of Nebraska Viticulture Program (firstname.lastname@example.org, email@example.com).
- When using any fungicides or insecticides, be sure to be aware of and follow pre-harvest intervals and re-entry times for crop quality and for you and your workers’ protection.