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Managing populations of the vine mealybug, Planococcus ficus (Hemiptera: Pseudococcidae), in Coachella Valley vineyards using inundative releases of the parasitoid, Anagyrus pseudococci (Hymenoptera: Encyrtidae), and baits to control the field ant, Formic

Posted on:2008-06-24Degree:Ph.DType:Dissertation
University:University of California, RiversideCandidate:Tollerup, Kristen ErikFull Text:PDF
The vine mealybug, Planococcus ficus, has become an important economic pest in California grape vineyards since it was accidentally introduced into the Coachella Valley in ca. 1994. Mealybugs feed on plant phloem and excrete honeydew which contaminates plants and reduces the salability of fruit. Coachella Valley growers rely on the systemic insecticide, Admire (imidacloprid) to control P. ficus. To manage economic populations of P. ficus and reduce the use of Admire, inundative releases of the encyrtid parasitoid and control of the ant, Formica perpilosa Wheeler were investigated.In 2002 and 2003 inundative release treatments of A. pseudococci were conducted at ca. 37,000 parasitoids per ha/week all release treatments also included applications of Admire. Inundative releases treatments significantly reduced populations of P. ficus below levels observed in the untreated control plots (2002) and Admire only plots (2003). No statistical separation occurred among release treatments in 2002 or 2003. The ant, F. perpilosa is native to the southwest United States and northern Mexico, yet little is known regarding its life-history and foraging characteristics. This species infests vineyards in the Coachella Valley and aggressively tends P. ficus, protecting it from natural enemies such as A. pseudococci as well as allowing it to overwinter and escape extreme summer temperatures on the vine roots.In vineyards, F. perpilosa nests are active from February thru October and brood is present from March thru September. F. perpilosa is seasonally polydomous and forms satellite nests from 2.13 to 6.39 m from home colonies. Mating flights occur in June and August but it was not determined where mating takes place.F. perpilosa nests were controlled using either 10 g anchovy bait (1% hydramethylnon) or 15 g Advance bait (0.011% abamectin) however, the treatments did not reduce the number of new nests that founded by newly mated queens flying into the vineyard.Controlling F. perpilosa had a negative impact on P. ficus populations. Mealybug populations fell to below a detectable level when the associated F. perpilosa nest was eliminated. An economic analysis of the baiting program to control ants was conducted.
Keywords/Search Tags:Ficus, Ant, Coachella valley, Vineyards, Inundative releases, Mealybug, Populations, Perpilosa
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