|Burks, Charles - Chuck|
|THOMSON, DONALD - Pacific Biocontrol|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2018
Publication Date: 2/11/2019
Citation: Burks, C.S., Thomson, D.R. 2019. Optimizing efficiency of aerosol mating disruption for navel orangeworm (Lepidoptera: Pyralidae). Journal of Economic Entomology. 112(2):763-771. https://doi.org/10.1093/jee/toy417.
Interpretive Summary: Experiments were conducted to improve cost-effectiveness of aerosol mating disruption for navel orangeworm, an insect pest of nut crops in California. Mating disruption is achieved by emitting pheremones into orchards so that male orangeworms can't find females, disrupting mating and, hence, reporduction. Small plot trials in 2015 revealed that increased frequency of emission increase impact on male location of a pheromone source, and that emission over only key portions of the night was as effective as the then-current practice of emitting for 12 hours. In 2017, a small plot experiment showed that aerosol emitters dispensing more concentrated pheromone more frequently suppressed male capture in pheromone traps as efficiently as aerosol dispensers placed more densely and emitting the same total amount of active ingredient less frequently over a longer period of the night. A season-long efficacy test in 2016 found that aerosol using parameters based on these experiments provided a near-complete suppression of navel orangeworm males in pheromone traps, and significantly less navel orangeworm damage in plots treated with this modified aerosol mating disruption regime. These findings demonstrate that the same total amount of pheromone (active ingredient) dispersed in a more concentrated form, more frequently, and from fewer point sources can provide significant protection from navel orangeworm with greater cost efficiency.
Technical Abstract: Improved cost efficiency for aerosol mating disruption for the navel orangeworm Amyelois transitella Walker (Lepidoptera: Pyralidae) was examined in experiments performed between 2015 and 2017. A programmable dispenser was used to explore the effects of frequency of treatment, time of night during which pheromone was emitted, and the concentration of pheromone used. A curvilinear trend indicated improved trap suppression with increased emission frequency in the range of 2 to 12 emissions per hour. A subsequent experiment found greater trap suppression when the same amount of active ingredient was emitted 7 times per hour compared to the same amount of material emitted at twice the concentration but half the frequency. Another experiment found no significant difference in cumulative trap suppression between treatment for the last four or six hours of the night compared to 12 hours, and a subsequent experiment comparing a current commercial mating disruption system emitting for 12 hours with a proposed alternative emitting more material per hour for fewer hours showed similar levels of suppression of males in pheromone traps. A season-long efficacy trial using dispensers deployed and programmed based on these findings demonstrated significant reduction of damage to Nonpareil almonds treated with mating disruption. These data reveal important information about the response of the navel orangeworm to aerosol mating disruption, which should provide improved cost-effectiveness. These findings for navel orangeworm are discussed in relation to studies of aerosol mating disruption for the codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae).