Comparison of seven essential oils identifies cubeb oil as an improved attractant for redbay ambrosia beetle, Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae)

The redbay ambrosia beetle, Xyleborus glabratus, is an exotic wood-borer that vectors the fungal agent (Raffaelea lauricola) responsible for laurel wilt disease.  Since its introduction into Georgia in 2002, X. glabratus has spread throughout the southeastern USA, and laurel wilt has decimated large populations of native Persea trees, particularly redbay (P. borbonia) and swampbay (P. palustris).  Currently, the lethal vascular disease threatens avocado (P. americana) in south Florida.  To control the spread of laurel wilt, effective attractants are needed for early detection of the vector.  Phoebe oil lures are the best known attractant for X. glabratus, but they are no longer available.  Current detection systems use commercial manuka oil lures, but our research indicated that manuka lures have a field life of 2-3 weeks in Florida.  Therefore, we evaluated seven essential oils as attractants for X. glabratus.  Several field tests were conducted in Florida to compare efficacy of manuka, phoebe, cubeb, ginger root, angelica seed, tea tree, and orange oils (all as whole oil preparations in membrane-based dispensers).  Tea tree and orange oils were not attractive; ginger and angelica oils were intermediate in attraction; and cubeb oil was just as attractive as fresh manuka and phoebe oils.  Subsequent tests with commercial formulations indicated that cubeb lures enriched in sesquiterpenes captured significantly more X. glabratus than manuka lures, were better for early detection at low population densities, and had increased longevity (at least 8 wk).  Based on these results, cubeb lures are now recommended for improved detection of X. glabratus.