Submitted to: Environmental Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/5/2006
Publication Date: 2/1/2007
Citation: Knight, A.L. 2007. Influence of within-orchard trap placement on catch of codling moth (lepidoptera: tortricidae) in sex pheromone-treated orchards. Environmental Entomology 36:425-432. Interpretive Summary: Codling moth is a serious pest of apple, pear, and walnut. Growers typically monitor this pest with traps baited with sex pheromone. I examined the influence of trap placement within orchards treated with sex pheromone on the catch of codling moth. Studies showed that male but not female moths fly toward the pheromone-treated plots. Traps placed on the upwind border of pheromone-treated plots caught high numbers of moths, while traps on the downwind border of plots caught few moths. Traps placed on the border of commercial orchards caught more moths than traps placed 30 - 50 m from the border. Interior traps more frequently failed to catch moths despite the presence of nearby fruit injury. These studies support the use of a standardized protocol that includes trap placement within orchards.
Technical Abstract: The influence of trap placement on catches of codling moth, Cydia pomonella (L.), was examined in orchards treated with sex pheromone dispensers. Mark-recapture tests with sterilized moths released along the interface of pairs of treated and untreated apple and pear plots found that significantly more male but not female moths were recaptured on interception traps placed in the treated plots. In a second test, significantly higher numbers of wild male and female moths were caught on interception traps placed in treated versus untreated plots within a heavily infested orchard. The highest numbers of male moths were caught on traps placed along the interior edge of the treated plots. Trap position had no influence on the captures of female moths. In a third test, north - south transects of sex pheromone-baited traps were placed through adjacent treated and untreated plots that received a uniform release of sterilized moths. Traps on the upwind edge of the treated plots caught similar numbers of moths as traps upwind from the treated plots. Moth catch was significantly reduced at all other locations inside versus outside of the treated plots, including traps placed on the downwind edge of the treated plot. In a fourth test, five commercial apple orchards were monitored with groups of sex pheromone-baited traps placed either on the border or at three distances inside the orchards. The highest moth counts were in traps placed at the border and the lowest moth counts were for traps placed 30 and 50 m from the border. In a fifth test, the proportion of traps failing to catch any moths despite local fruit injury was significantly higher in traps placed 50 versus 25 m from the border.