The vine mealybug is an emerging problem in grape production and its breeding habits promote the spread of the pest. “The mealybugs really don’t move quickly,” says Cooperative Extension Specialist Kent Daane. “However when you think about a population over the years, it gets very large on one vine and starts getting a little bit crowded as they put out a lot of honeydew. It’s good for the mealybug to move away to the next vine and find a clean feeding source. That’s usually what we call the crawlers.”
Daane says several things can aid in spreading the slow-moving pest. “They can also be picked up the by field workers or harvest equipment. They can be blown by wind and be picked up even by things like birds. We often times see new infestations underneath power lines or by riparian zones because that’s where bird are going to, and back from, in vineyards,” Daane said.
More about the vine mealybug
From the UC IPM website: Damage by the vine mealybug is similar to that of other grape-infesting mealybugs in that it produces honeydew that drops onto the bunches and other vine parts and serves as a substrate for black sooty mold. If ants are not present, a vine with a large population of this pest can have so much honeydew that it resembles candle wax. Also, the mealybug itself will be found infesting bunches making them unfit for consumption. Like the grape, obscure, and longtailed mealybugs, vine mealybug can transmit grapevine leafroll-associated viruses. Read more about the vine mealybug.