Factors Affecting the Differential Capture of Male and Female Codling Moth (Lepidoptera: Tortricidae) in Traps Baited with Ethyl (E, Z)-2,4-Decadienoate

Studies were conducted in apple to evaluate factors that differentially affect the catch of male and female codling moth, Cydia pomonella L., in traps baited with ethyl (E, Z)-2,4-decadienoate (pear ester). We examined the time of moth capture in the diel cycle and the recapture rates of marked moths in sex pheromone mating disruption (MD) and untreated orchards. The attractiveness of pear esterÐbaited trapswas comparedamongÞveapple cultivars.Experiments also assessed the inßuence of trap height, the distance of the trap from sex pheromone dispensers, proximity of foliage surrounding the trap, trap size, and proximity of adjacent clean and codlingmothÐinjured fruit on moth captures. The responses of male and female moths signiÞcantly differed in response to many of these factors. For example, the timeof peak female capture occurred earlier than formales.Ahigher proportion of recaptured, marked moths were females in MD versus untreated orchard plots. SigniÞcantly more male but not female moths were caught in traps placed high versus low in the tree canopy.Trapsplacedon theperimeterof thecanopycaught signiÞcantlymore femalemoths than traps placed within the canopy and surrounded by foliage. Smaller trap surfaces caught signiÞcantly more males than females. Traps placed adjacent to uninjured fruit caught signiÞcantly more females than traps placed away from fruit. No differences occurred between sexes in response to other factors: signiÞcantly higher counts of both sexes occurred in blocks of ÔGranny SmithÕ versus four other apple cultivars; recapture rates ofmarkedmothswere not different at release points ranging from 10 to 50m for either sex; and trap placement relative toMDdispensers or injured versus uninjured fruits was not a signiÞcant factor affecting moth catches or their sex ratio. Effective monitoring for either or both sexes of codling moth should consider standardizing these factors. Lure and kill strategies should include factors that optimize the captures of female moths.