Assessing the mating status of female codling moth (Lepidoptera: Tortricidae) in orchards treated with sex pheromone using traps baited with ethyl (E, Z)-2,4-decadienoate

Whether sticky traps baited with ethyl (E, Z)-2,4-decadienoate (pear ester) can be used to accurately assess the mating status of female codling moth, Cydia pomonella L., was evaluated in a series of tests. The proportion female moths caught in these traps that were virgin was compared with catches using interception and light traps in two separate studies. The mean proportion of virgin female codling moths caught in pear ester-baited traps was significantly lower than caught with either interception or light traps. Results were similar in both untreated and sex pheromone-treated orchards. Cohorts of virgin and mated female codling moths were flown separately to a pear ester-baited trap placed overnight in a flight tunnel. The recapture rate of virgin moths was significantly lower than for mated moths. The relation of the mean proportion of females mated versus the density of female moths caught in pear ester-baited traps over the entire season was examined by grouping data from 180 traps into eight density classes from 1 to > 20 female moths per trap per season. A significantly higher mean proportion of virgin females were caught in the lowest density class (one moth per trap) than in all other classes. Traps catching two female moths per season had a significantly higher proportion of virgin moths than traps catching 4-5, 9-15, and 16-20 moths. No significant differences in the proportion of virgin moths occurred among traps grouped into classes from 3 to >20 female moths caught per season. These data are consistent with action thresholds previously established for cumulative catch of female moths in pear ester- baited traps (at least one moth) and support the use of this kairomone to assess the potential efficacy of sex pheromone programs.