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We found significant differences in numbers of parasites recovered from release versus non-release areas of the same fields. From parasite pre-release samples in 1998 nearly twice as many parasites were recovered from 1997 parasite release areas as were recovered from areas where no parasites were released. More than 166,000 Anagyrus pseudococci early instar parasites of vine mealybug (VMB) and Leptomastidea abnormis late instar and adult VMB parasites were released from March through June. All parasites tested survive, find, and parasitize VMB through winter, spring, and hot summer conditions, based on positive results obtained throughout the test periods from both caged and open field trials. From several sampling techniques tested to estimate relative numbers of VMB and VMB damage, and relative numbers and movement of parasites, visual observations for relative estimates of VMB numbers and VMB damage and yellow sticky-cards were the most reliable, cost effective, and feasible. Ant control was assessed by using Maxforce (Tejara) ant bait. Early season results under cool temperatures and low level ant activity was positive with more parasites recovered from bait areas versus no bait areas. Results later in the season suggest that larger areas need to be treated for ant control when temperatures are high and ants are actively foraging. Higher yields were obtained from chemically untreated areas including parasite release and completely untreated, compared with yields from surrounding vineyards treated two times with Lannate to kill VMB. Lowest yields and highest levels of VMB were from areas with the highest numbers of insecticide applications.
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