Lodi, Calif.—Management of vine mealybug (VMB) in California vineyards has been problematic because of this pest’s high reproduction potential with multiple generations and a year-round presence with life stages that overwinter under vine bark, where it is difficult to apply treatments.
 

The vine mealybug (VMB) causes damage by feeding on grape clusters and vine parts where it produces honeydew that provides a medium for mold growth and makes grapes unmarketable. In addition, the VMB is a vector of grapevine leafroll-associated viruses.
 

The Lodi Winegrape Commission’s (LWC) recently formed the Mealybug Biocontrol Research Focus Group, which held a field day Aug. 8 to educate growers in field identification and management of the VMB, and the identification of parasitized mealybugs and insects that are effective mealybug predators. LWC research and education director Dr. Stephanie Bolton coordinates the focus group’s activities as the principal investigator for a two-year project funded by the American Vineyard Foundation. “A primary objective for the research focus group is to educate growers on what we can do to integrate more biocontrol into our normal integrated pest management (IPM) programs and spraying activities,” Bolton said.
 

Organic grower Jay Leone hosted the field day in a 30-acre block of Cabernet Sauvignon that has a high endemic population of the parasitic wasp. Releases of the wasp have been made for VMB control, and it has established populations in many vineyard regions. 
 

Leone’s vineyard is more than 20 years old and was originally farmed conventionally. Leone bought the vineyard seven years ago and converted it to organic production. With the high populations of parasitic wasps, the VMB is kept in check, mostly confined to lower portions of the vine without causing fruit damage. 
 

According to Bolton, the first step of integrating biocontrol into VMB management is: “Don’t kill the good insects!”
 

In addition to Anagyrus wasps, other VMB predators include Cryptolaemus montrouzieri, a type of lady beetle also called the mealybug destroyer, and lacewings, which also prey upon leafhoppers. Beneficial insects found in Lodi vineyards that control mites are six-spotted thrips, minute pirate bugs and predatory mites. Parasitic wasps and flies can control caterpillars and omnivorous leafrollers. Predaceous midge flies in the family Cecicomyiidae can feed on mealybug eggs and larvae in some California vineyards.
 

To assist growers, the LWC focus group produced and distributed a table that lists the major pesticides registered for vineyard use in California based on the potential effects on beneficial insects. The chart is available at lodigrowers.com/growereducation/videospresentationshandouts.