Evaluation of Lure Combinations Containing Essential Oils and Volatile Spiroketals for Detection of Host-Seeking Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae).

The invasive redbay ambrosia beetle, Xyleborus glabratus Eichhoff (Coleoptera: Curculionidae: Scolytinae), vectors the fungal pathogen (Raffaelea lauricola) that causes laurel wilt, a disease responsible for widespread mortality of trees in the Lauraceae in the southeastern United States. Early detection of incipient vector populations may allow for management practices that could successfully mitigate damage. Developing new, highly effective attractants is a priority for improving sensitivity of early detection efforts. In this study, two field tests were conducted to evaluate combinations of commercially available bark and ambrosia beetle lures for enhanced attraction of host-seeking female X. glabratus. In addition, lures were compared for capture of nontarget scolytine beetles. In the first experiment, traps baited with a combination of cubeb oil, conophthorin, chalcogran, and ethanol captured greater numbers of X. glabratus than cubeb oil alone, the current standard attractant. However, this combination lure resulted in higher nontarget scolytine captures than with the cubeb lure. In the second field test, an oil enriched in the sesquiterpene α-copaene caught significantly more X. glabratus than other lures currently available for monitoring this pest. There were no differences in efficacy between cubeb oil lures produced by two different manufacturers, and a combination lure containing copaiba and cubeb oils did not increase captures over the cubeb lure alone. Results of these two tests suggest that increased sensitivity for detection of X. glabratus may be achieved with a multicomponent lure that incorporates α-copaene, spiroketals, and low release of ethanol.