Be wary of pesticide blends
Doug Walsh cautions growers from using synthetic pyrethroids as insecticides, which can cause spider mite flare-ups.
Washington State University entomologist Dr. Doug Walsh is worried about a trend he is seeing in pesticide registrations of new compound materials, a trend he believes could disrupt the balance of ecological systems. What Walsh finds alarming is a move by some chemical companies that are going to a "custom blend" of two or more insecticides as a way to improve the product but also make it harder for other companies to compete when pesticides go off patent.
He explained that because of the length of time it takes for registration approval from the U.S. Environmental Protection Agency, there is frequently only a short window when the material is under patent. Companies have found that combining two or more of their pesticides into a new blend can help extend the life of patented products.
He pointed out that Syngenta recently registered Endigo, a blend of Warrior (cyhalothrin) and Actara (thiamethoxam) insecticides, while Bayer Crop Science released Leverage, a blend of Provado (imidacloprid) and Baythroid (cyfluthrin). Though these chemicals target cotton and potatoes, similar blends will be coming for wine grapes, he said.
"The labels cover a laundry list of insects that they can control," he said. "But the bad news here is that you've got pyrethroids in the mix as well. With the pyrethroids, I think there's great potential for having secondary outbreaks of spider mites and what not. These types of insecticides will really throw your balance of the ecological system off fast."