Effects of Various Semiochemicals on the Responses of Rhyzopertha dominica to Pheromone Traps in the Field

Abstract

Abstract Feeding male Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) produces two pheromones Dominicalure-1 (DL-1) and Dominicalure-2 (DL-2), which attracts adults of both sexes. In field experiments conducted in Oklahoma, R. dominica captures in multiple funnel traps deployed with its pheromones, ethanol, or both, green-leaf volatiles (GLV), plant essential oils, or synthetic pheromones for Ips spp., Dendroctonus spp., or Scolytus multistriatus (Marsham) (Coleoptera: Scolytidae) were examined. The bark beetle lures were evaluated at the release rate recommended for the respective insects. The number of insects trapped increased when R. dominica lure was combined with ethanol, whereas beetle captures neither were enhanced nor inhibited when the lure was combined with GLV, 3-methylcyclohex-2-en-l-one (MCH), or plant essential oil mixtures turpentine, from Pinus spp., and cedar wood oil, from Juniperus spp. (Coniferales: Pinaceae and Cupressaceae). Similarly, the numbers of captured R. dominica did not significantly differ when R. dominica lures were supplemented with ipsdienol, ipsenol, cis-verbenol, or pityol. Conversely, the combination of R. dominica lures with exo-brevicomin, frontalin, and commercial lure for S. multistriatus, containing the bicyclic ketal multistriatin, resulted in significantly fewer captures of R. dominica. The presence of live males of the closely related species Prostephanus truncatus (Horn) decreased the number of captured R. dominica by >70% compared with captures in traps baited with R. dominica's natural pheromone alone. Results support the hypothesis that grain-infesting R. dominica evolved from forest-inhabiting ancestors and retained behavioral traits for semiochemical interactions with other wood-boring beetle species. Such interspecific interactions have potential for exploitation in pest management programs against R. dominica.