Name: Matt Boughner, Viticulturist, Diamond West Farming, Inc.
Location: Central California
Overview: We have used the deer and squirrel repellent spray to protect 800–1,000 acres of grape vines for 3 years and had the best results in 2015. The first year we sprayed below the vegetative zone to minimize risk of phytotoxicity. Even with a dramatic reduction in animal damage, spraying this product alone proved to be a significant labor challenge. In 2014 we repeated the process while spot spraying the vegetative zone to test for safety. In 2015 we tank mixed Plantskydd with our first 2 applications of fungicide and sprayed all 800 acres.
Timing of application: Our experience is that the core of the damage occurs very early in the growth phase. As with any pest or disease, timing of application is everything. Deer will tear at fruiting buds starting at around 4” and squirrels can clip the buds as they are swelling. Vegetative growth can and will recover but the associated fruit loss is unacceptable. For this reason, I will begin our fungicide/Plantskydd application as soon as possible, potentially earlier than previous practice. Once Plantskydd is applied, the damage virtually stops and so long as a follow up application is made 10-14 days later, the vines get through the critical phase.
Full report & Pictures: 2016 VMI Field Trial Report PDF