Research Reports: Responses of Hylastes Salebrosus to Turpentine, Ethanol, and Pheromones of Dendroctonus (Coleoptera: Scolytidae)

Abstract

Attraction of the pine bark beetle Hylastes salebrosus Eichhoff to the host chemicals turpentine and ethanol, and the Dendroctonus pheromones frontalin and exo-brevicomin, were assessed in four field trapping experiments. H. salebrosus were attracted to turpentine alone, and the addition of ethanol, whether mixed with the turpentine or deployed at any of three different release levels, elicited a significant increase in attraction. In another experiment incorporating all semiochemicals tested, beetles were more attracted to traps baited with the combination of the turpentine:ethanol mix, frontalin, and exo-brevicomin, than to traps with the turpentine:ethanol mix only. A final pair of experiments determined that exo-brevicomin, and not frontalin, deployed with turpentine was important for eliciting attraction. H. salebrosus may produce and use exo-brevicomin as an attractive pheromone, but the data also suggest that H. salebrosus can exploit exo-brevicomin as a kairomone from other scolytid species that colonize the same pine resource.