Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/2/2017
Publication Date: 2/8/2017
Citation: Burks, C.S. 2017. Combination phenyl propionate/pheromone traps for monitoring navel orangeworm (Lepidoptera: Pyralidae) in almonds in the vicinity of mating disruption. Journal of Economic Entomology. 110(2):438-446. doi: 10.1093/jee/tow318.
Interpretive Summary: Mating disruption for navel orangeworm, used in an increasing proportion of almond and pistachio orchards, is a least-toxic pest management alternative that decreases populations of and damage from this pest, but also makes detection with pheromone lures more difficult in both the treated block and neighboring blocks. Previous studies showed that a combination phenyl propionate/pheromone lure attracts similar numbers of adults compared to pheromone-only lures in the absence of mating disruption, and more adults than either lure type alone in the presence of mating disruption. Data from the current study demonstrate a field life of 6 weeks for phenyl propionate dispensers, and indicate that the number of adults captured was similar across different intensities of mating disruption in experimental plots. Data from monitoring sites 0.6 to 2.8 miles from large commercial mating disruption blocks indicated that phenyl propionate/pheromone combination traps detected navel orangeworm under conditions in which traps baited only with pheromone were partially or completely suppressed. These findings indicate that phenyl propionate/pheromone combination traps will be useful for monitoring for navel orangeworm, the key insect pest of the $7.8 billion almond and pistachio industries, in areas in which mating disruption is commonly used.
Technical Abstract: Aerosol mating disruption is used for management of navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), in an increasing portion of California almonds and pistachios. This formulation suppresses pheromone monitoring traps far beyond the treatment block, potentially complicating monitoring and management of this key pest in such blocks. Phenyl propionate is an attractant that captures adults in the presence of mating disruption which completely suppresses pheromone traps, and lures combining phenyl propionate with a pheromone lure (PPO-combo lure) synergize trap capture in the presence of mating disruption. In this study, laboratory and field studies of different phenyl propionate dispensers indicate a useful life of six weeks for the phenyl propionate lures. Controlled experiments found similar levels of capture in phenyl propionate and PPO-combo lures in the presence of varying levels of mating disruption intensity. A subsequent trial compared monitoring of field plots at various distances from fields under commercial mating disruption for much of the season with pheromone and PPO-combo lures. While there was some evidence of partial suppression of capture in PPO-combo traps closer to mating disruption compared to lures farther away, there was not a failure of detection as occurred with pheromone lures. The ratio of adults in pheromone and PPO-combo trap varied with proximity from treated fields. These results indicate that, in addition to monitoring in mating disruption plots, phenyl propionate lures can be useful for insuring against failure of detection of navel orangeworm pressure in areas where mating disruption is widely used.