Comparison of Sex Pheromone and Kairomone-Enhanced Pheromone Lures for Monitoring Oriental Fruit Moth (Lepidoptera: Tortricidae) in Mating Disruption and Non-Disruption Tree Fruit Orchards

Abstract

Oriental fruit moth, Grapholita molesta (Busck), populations were monitored using standard sex pheromone lures (OFM L2) and kairomone-enhanced lures to aid the interpretation of trap captures with enhanced relative to conventional lures. Initially, comparison of 10 different lures showed that a10X load of OFM pheromone, codlemone, terpinyl acetate, and acetic acid were key components of the most attractive lures (TRE11034 and 1123). Subsequent trapping studies in mating disruption and non-disrupted orchards in the United States and Spain compared trap captures with TRE1123 and OFM L2 lures. Compared to the OFM L2 lure, the TRE1123 lure captured more moths in mating disruption and non-disrupted orchards, caught female moths, improved the precision of mean population estimates, and led to greater resolution of generational flights. Suppression of trap captures in mating disruption versus non-disrupted orchards was similar with both lures. There were significant linear correlations between weekly trap captures with the two lures in the majority of mating disruption and non-disrupted orchards across locations and years. Furthermore, regression of the slopes of trap capture regressions (i.e., attractiveness of enhanced lures relative to sex pheromone lures alone) versus moth density (as measured by mean cumulative moth capture with TRE1123 and OFM L2 lures) exhibited a significant positive relationship in non-disrupted orchards, indicating enhanced lures were relatively more attractive under high population densities. This relationship was not significant in mating disruption orchards, likely due to the density independent, non-competitive mechanism of mating disruption for oriental fruit moth when using high-dose reservoir dispensers.

Keywords: Grapholita molesta; pheromone trapping; semiochemical; sex pheromone.