Controlling mealybug populations in vineyards is a critical component of mitigating damage that can be caused by grape leafroll associated virus. Strategies for mealybug control were one of the significant topics of discussion at the 2019 Sustainable Ag Expo, which also featured the International Sustainable Wine Summit for the first time in the United States.
“We talked about the relationship between the mealybug as a vector and leafroll as the pathogen and that helps determine what insecticides you want to use,” said Kent Daane, Biological Control Specialist for UC Berkeley. “If you’re thinking about mealybug as just damaging the fruit, we can take a small population within the vineyard. If you’re thinking about mealybug as a vector, we really want to drive that population down low.”
There are several different insecticide materials that are available to growers which can provide varying levels of mealybug control. An insect growth regulator can also be effective in managing mealybug populations, but its use can present challenges for some growers. “It’s not being used as much by winegrape growers because of worries about residuals, about material getting into the winegrapes, and because of European restrictions,” Daane noted.
As with insecticides, there are more and more mating disruption materials that are becoming available to growers. Incorporating more than one approach into an integrated pest management system can provide for the best results in controlling mealybug pressure. Biological control methods also present a host of choices for growers to choose from.
“The ones you can purchase would be the Anagyrus pseudococci, the Mealybug Destroyer, and the green lacewing,” said Daane. “Of those three, I like the Anagyrus (the parasite), I like the Mealybug Destroyer. I’m not a fan of releasing green lacewings for mealybug control. They’re great against aphids, not as good against mealybugs.”
Listen to Daane’s interview below.