Location: Subtropical Horticulture ResearchTitle: Temporal analysis of sesquiterpene emissions from manuka and phoebe oil lures and efficacy for attraction of Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae) Author
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/21/2012
Publication Date: 4/1/2012
Citation: Kendra, P.E., Niogret, J., Montgomery, W.S., Sanchez, J., Deyrup, M.A., Pruett, G.E., Ploetz, R.C., Epsky, N.D., Heath, R.R. 2012. Temporal analysis of sesquiterpene emissions from manuka and phoebe oil lures and efficacy for attraction of Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae). Journal of Economic Entomology. 105(2):659-669. Interpretive Summary: The redbay ambrosia beetle (RAB) is an exotic wood-boring pest that transmits laurel wilt, a deadly fungal disease threatening the avocado industry in Florida. There is a critical need for effective lures to detect, monitor and control the spread of this invasive pest. Scientists at the USDA-ARS in Miami, FL conducted field tests to (1) evaluate efficacy of commercial lures of manuka oil and phoebe oil, and (2) determine the best trap type to optimize detection of RAB. They also measured the emission of volatile attractants from the two lures. In field tests, phoebe lures captured significantly more RAB than manuka lures, and sticky traps captured more RAB than funnel traps. Phoebe lures captured beetles for 10-12 weeks, but manuka lures lost efficacy after 2-3 weeks. Emissions of attractants decreased rapidly from both lures, but three chemicals (a-copaene, a-humulene, and cadinene) were consistently higher from the more attractive phoebe lures. Results indicated that the current RAB detection system (funnel traps baited with manuka lures) is suboptimal, due to limited longevity of the field lure. Information from this study will be used by action agencies (Florida DPI, CAPS) engaged in monitoring programs for RAB, and will provide the foundation for researchers to develop improved lures for RAB.
Technical Abstract: Redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is an exotic wood-borer that vectors the fungal agent (Raffaelea lauricola) responsible for laurel wilt disease. Laurel wilt has had a severe impact on forest ecosystems in the southeastern USA, killing a large proportion of the native Persea trees, particularly redbay (P. borbonia) and swampbay (P. palustris), and currently poses and economic threat to avocado (P. americana) in Florida. To control the spread of this lethal disease, effective attractants are needed for early detection of the vector. Parallel 12-wk field tests were conducted at two sites in Florida to evaluate efficacy of two host-based semiochemical lures, manuka oil and phoebe oil, and relate captures of X. glabratus to release rates of putative sesquiterpene attractants. Two trap types were also evaluated – Lindgren funnel traps and sticky panel traps. To document lure emissions over time, a separate set of lures was aged outdoors for 12 wk and sampled periodically to quantify volatile sesquiterpenes using super-Q adsorbant and GC-MS analysis. In both field tests, phoebe lures captured significantly more X. glabratus than manuka lures, and sticky traps captured more beetles than funnel traps. Phoebe lures captured X. glabratus for 10-12 wks, but field life of manuka lures was 2-3 wks. Chemical analysis revealed that emissions of a-copaene, a-humulene, and cadinene were consistently higher from phoebe lures, particularly during the 2-3 wk window when manuka lures lost efficacy, suggesting that these sesquiterpenes are likely primary kairomones utilized by host-seeking females. Results indicate that the current monitoring tool (manuka-baited funnel trap) is suboptimal for early detection of X. glabratus due to rapid depletion of sesquiterpenes from the lure.