Estimating plume reach and trapping radii for male and female Cydia pomonella (Lepidoptera: Tortricidae) captured in pheromone-kairomone baited traps in Washington State apple orchards under mating disruption.

Abstract

Male Cydia pomonella (L.) (Lepidoptera: Tortricidae) dispersion has largely been studied in nonmating disrupted orchards due to synthetic pheromone interference with capture in monitoring traps. Little is known about female dispersion. This study aimed to characterize male and female dispersion in mating disrupted commercial apple orchards. Sterile C. pomonella recapture data from single-trap multiple-release experiments using PHEROCON CM-DA COMBO + AA Lure-baited orange Pherocon VI delta traps was interpreted to determine pheromone-kairomone lure-baited trap effective area, trap deployment density for effective monitoring, and absolute male and female C. pomonella density in mating disrupted Washington commercial apple orchards. The maximum plume reach of the pheromone-kairomone lure in mating disrupted orchards was <5 m from the baited trap for both sexes. Maximum dispersive distances for 95% of the released C. pomonella in mating disrupted orchards were 106 and 135 m for males and females, yielding trapping areas of 3.87 and 6.16 ha, respectively. Estimates were consistent across 3 growing seasons and represent the first records of male and female dispersal distance and monitoring trap efficacy from commercial C. pomonella mating disrupted apple orchards. With relevance to commercial monitoring programs and economic thresholds in mating disrupted orchards, traps should be deployed at a density of 1 per 3-6 ha. Capture of a single male or female C. pomonella corresponds to at least 82-104 C. pomonella within the 3-6 ha trapping area. This refined C. pomonella capture interpretation in pheromone-kairomone baited traps in mating disrupted commercial apple orchards yields more precise damage estimates and assists in insecticide-use decision making.