Four species of mealybug feed on grapes in California. They suck out plant content and excrete unused plant material. The result is a layer of sticky, wet honeydew on which thick, black, sooty mold grows. The strict quality standards set by the grape industry and demanded by consumers have led to a dependence on insecticides for controlling mealybug populations.

“Although more vineyards are becoming infested, populations within infested areas are declining because the judicious use of insecticides has successfully lowered mealybug populations in areas that are infested.”

“Season-long control programs for vine mealybug are typically comprised of a combination of insecticide treatments assisted by biological control. … Promoting parasites is very important because they are active late in the growing season and can reduce vine mealybug populations before the pest begins to move to the lower part of the trunk after harvest [where they are protected from insecticides].”

Authors: Chuck Ingels, David Haviland and Steve Quashnick*
Affiliation: UC Cooperative Extension and *Wilbur Ellis
Title: Vine mealybug management in wine grapes in the northern San Joaquin Valley.
Publication: CAPCA Adviser (2012) April:34-37.