Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2006
Publication Date: November 1, 2006
Citation: Knight, A.L. 2006. 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. Environmental Entomology 35:894-900. Interpretive Summary: The pear ester is an odor released from ripening pears. This compound can be used to lure both male and female moths into sticky traps, which allow growers to more easily, monitor its seasonal populations. The mating status of female moths caught in traps baited with pear ester was found to be biased for mated over virgin moths. Thus determining the proportion of female moths within orchards treated with sex pheromones with this lure would under estimate the level of mating disruption in the population. This bias also means that the effectiveness of using pear ester to attract and kill female moths and limit the number of eggs laid is reduced. A significant increase in the proportion of female moths that were virgin within apple plots was only found when traps caught < 2 females per season. These data are useful in establishing moth catch thresholds that can be used to recommend the additional application of insecticides.
Technical Abstract: The proportion of female codling moth, Cydia pomonella (L.), that were unmated in sticky traps baited with ethyl (E, Z)-2,4-decadienoate (pear ester) was compared with catches in interception and light traps. The proportion of female moths that were unmated was significantly lower in pear ester-baited traps than with either of these 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 females was significantly lower than for mated females. 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 191 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 (1 moth per trap) than in all other classes. These data are consistent with action thresholds previously established for cumulative catch of female moths in pear ester-baited traps (> 1 moth), and support the use of this kairomone to assess the potential efficacy of sex pheromone programs.