Efficacy of a-copaene, cubeb, and eucalyptol lures for detection of redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae)

Authors: Kendra, Paul; Montgomery, Wayne; Schnell, Elena; DEYRUP, MARK - Archbold Biological Station; Epsky, Nancy

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2016
Publication Date: 12/1/2016
Citation: Kendra, P.E., Montgomery, W.S., Schnell, E.Q., Deyrup, M., Epsky, N.D. 2016. Efficacy of a-copaene, cubeb, and eucalyptol lures for detection of redbay ambrosia beetle (Coleoptera: Curculionidae: Scolytinae). Journal of Economic Entomology. 109(6):2428-2435.

Interpretive Summary: The redbay ambrosia beetle (RAB) carries a fungus that causes laurel wilt, a lethal disease of U.S. trees in the laurel family. Over the past decade, laurel wilt has decimated redbay and swampbay forests along the southeastern coastal plain, and now threatens Florida’s production of avocado, valued at $21.6 million for the 2014-2015 season. Effective lures are needed to detect RAB and control its spread. Commercial cubeb lures are the current standard used for detection of RAB, but recent research identified two new lures: a-copaene (developed by USDA-ARS, Miami, FL) and eucalyptol. Scientists at the USDA-ARS (Miami, FL), in collaboration with Archbold Biological Station (Lake Placid, FL) conducted lab and field studies to compare efficacy of the three lures. Results indicated that the copaene lure is the best RAB lure currently available, with field longevity of 3 months. This information will benefit action agencies that monitor for RAB by providing a more attractive, long lasting lure for better pest detection.

Technical Abstract: Redbay ambrosia beetle, Xyleborus glabratus Eichhoff, is a wood-boring pest that has now invaded nine states in the southeastern USA. The beetle’s dominant fungal symbiont (Raffaelea lauricola) is phytopathogenic, inducing laurel wilt in trees within the family Lauraceae. Members of the genus Persea are particularly susceptible to the lethal disease, including native redbay (P. borbonia) and swampbay (P. palustris), as well as commercial avocado (P. americana). Cubeb oil lures are the current standard for detection of X. glabratus, but recently eucalyptol and a 50% a-copaene oil have been identified as additional attractants. This study used a combination of binary-choice bioassays, field cage release-and-recapture assays, and a 12-wk field trial to compare efficacy of eucalyptol and copaene lures relative to commercial cubeb lures. In addition, GC-MS was used to quantify emissions from lures field-aged for 12 wk. In laboratory bioassays, copaene lures were more attractive than eucalyptol lures. In field cage assays, copaene lures recaptured a higher percentage of released beetles than cubeb lures. In the field test, cubeb lures captured fewer beetles than copaene lures, and lowest captures were obtained with eucalyptol lures. Combining eucalyptol with either copaene or cubeb lures did not increase captures over those lures deployed alone. Both copaene and cubeb lures were effective in attracting X. glabratus for 12 wk, but field life of eucalyptol lures was only 4 wk, consistent with the quantification of lure emissions. Results suggest that the 50% a-copaene lure provides the best pest detection currently available for X. glabratus.