H12-P CONTROL OF THE VINE MEALYBUG, PLANOCOCCUS FICUS, ON GRAPE IN THE COACHELLA VALLEY USING PARASITOIDS AND ANT CONTROL *Kris Tollerup, John Klotz, and Daniel Gonzalez Department of Entomology, University of California, Riverside, CA 92521 Field releases of the parasitoid, Anagyrus pseudococci (Girault), in conjunction with control the field ant, Formica perpilosa (Wheeler) significantly reduced the total number of vine mealybugs infesting grapevines. Experiments were conducted on three vineyards (two Superior Seedless Grape vineyards and a Thompson Seedless Grape vineyard) during the 2000 - 2001 and 2001 - 2002 growing seasons. Each ranch had a single experimental block divided into five plots of ca. 0.63 ha each. All plots except the control plots were treated with Lorsban (chlorpyrifos) to control F. perpilosa and two field-rate applications of Admire (imidacloprid). Lorsban applications were restricted to a 0.5 m wide strip of soil directly beneath the grapevines in order to avoid the vine trunk and concentrate the insecticide at the base of the vines where F. perpilosa nests. Parasitoids were released at 15,000 per week beginning either 12 weeks prior to harvest (high release rate), for 9 weeks beginning in March to mid May (medium release rate), or for four weeks beginning in late April (low release rate). Chlorpyrifos provided control of F. perpilosa for between 3 & 4 weeks. Populations of F. perpilosa rebounded at a critical period just prior to harvest; additional applications of Lorsban could not be applied due to a 76-day pre-harvest interval. This trial also focused on developing ant low-toxic baits to replace chlorpyrifos. Bait preference trials were conducted and indicate that anchovy bait with the active ingredient imidacloprid is highly preferred by F. perpilosa.