Sex Pheromone Dispenser Type and Trap Design Affect Capture of Dogwood Borer

Abstract

Using a ternary sex pheromone blend [86:6:6 v:v:v (Z,Z)-3,13-octadecadienyl acetate: (E,Z)-2,13-octadecadienyl acetate: (Z,E)-3,13-octadecadienyl acetate], we tested the effect of dispenser type and trap design for capture of dogwood borer (DWB), Synanthedon scitula Harris (Lepidoptera: Sesiidae) in apple orchards in West Virginia, Virginia, and North Carolina. Wing-style sticky traps baited with polyethylene vial pheromone dispensers captured more male DWB over the first 2 months than traps baited with rubber septum pheromone dispensers. However, catches in vial-baited traps decreased considerably after the first 2 months, possibly due to the antagonistic effect of 3,5-di-tert-butyl-4-hydroxy acetophenone that diffused from the polyethylene vials. By contrast, traps baited with rubber septum dispensers captured DWB males for at least 6 months; over the last four months of the flight season, catches in traps baited with a rubber septum were greater than those in traps baited with a vial dispenser. Therefore, the rubber septum dispenser is recommended for season-long monitoring of DWB. A release-rate study, using laboratory and field-aged dispensers, demonstrated that desorption of DWB sex pheromone from polyethylene vial or rubber septum dispensers followed first order kinetics, with half-lives of 1.6 and 10.7 months, respectively. Several trap designs, including wing-and delta-style sticky traps, and white and green "bucket-style" traps, baited with rubber septum dispensers were compared in commercial apple orchards for catch of DWB. Bucket traps caught more moths when moth populations were high, because the sticky surfaces of the 1C and delta traps likely became saturated. However, among the commercially available traps tested, no particular design gave consistently higher catches. Further work is needed to explore capture mechanisms and maintenance needs of different trap types.