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

Abstract

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 ester–baited traps was compared among five apple cultivars. Experiments also assessed the influence 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 codling moth–injured fruit on moth captures. The responses of male and female moths significantly differed in response to many of these factors. For example, the time of peak female capture occurred earlier than for males. A higher proportion of recaptured, marked moths were females in MD versus untreated orchard plots. Significantly more male but not female moths were caught in traps placed high versus low in the tree canopy. Traps placed on the perimeter of the canopy caught significantly more female moths than traps placed within the canopy and surrounded by foliage. Smaller trap surfaces caught significantly more males than females. Traps placed adjacent to uninjured fruit caught significantly more females than traps placed away from fruit. No differences occurred between sexes in response to other factors: significantly higher counts of both sexes occurred in blocks of ‘Granny Smith’ versus four other apple cultivars; recapture rates of marked moths were not different at release points ranging from 10 to 50 m for either sex; and trap placement relative to MD dispensers or injured versus uninjured fruits was not a significant 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.