Utility of essential oils for development of host-based lures for Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), vector of laurel wilt

Authors: Kendra, Paul; Montgomery, Wayne; Niogret, Jerome; Tabanca, Nurhayat; OWENS, DAVID - Orise Fellow; Epsky, Nancy

Submitted to: Open Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2018
Publication Date: 5/8/2018
Citation: Kendra, P.E., Montgomery, W.S., Niogret, J., Tabanca, N., Owens, D., Epsky, N.D. 2018. Utility of essential oils for development of host-based lures for Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), vector of laurel wilt. Open Chemistry. 16:393-400.

Interpretive Summary: The invasive redbay ambrosia beetle (RAB) carries a fungus that causes laurel wilt, a lethal disease of trees in the laurel family, including US forest species (like redbay and swampbay) and avocado, an economically important fruit crop. Effective lures are needed for early detection and control of RAB to slow the spread of laurel wilt disease. Previous ARS research identified a-copaene as a strong host-based attractant for dispersing RAB, but this chemical is difficult to synthesize and too expensive for use in lures for pest detection and monitoring. Consequently, scientists at the USDA-ARS (Miami, FL) evaluated various plant-derived essential oils naturally high in a-copaene and other RAB host attractants. This report summarizes the efficacy of essential oil lures for RAB, including the initial use of manuka and phoebe oil lures, the current cubeb oil lure, and a newly-developed distilled oil lure enriched to contain 50% a-copaene. The enriched a-copaene lure, now available commercially, is the best attractant identified to date for detection of RAB, with longevity of 3 months. In addition, this lure was recently found to be effective for detection of Euwallacea nr. fornicatus, another invasive ambrosia beetle that vectors Fusarium dieback disease in avocado and other trees. This information will benefit avocado growers and action agencies that monitor for RAB and other pest ambrosia beetles in the US and Mexico.

Technical Abstract: Redbay ambrosia beetle, Xyleborus glabratus, is native to Southeast Asia, but subsequent to introduction in Georgia in 2002, it has become a serious invasive pest in the USA, now established in nine southeastern states. Females vector Raffaelea lauricola, the fungus that causes laurel wilt, a lethal vascular disease of trees in the family Lauraceae. Laurel wilt has caused extensive mortality in native Persea species, including redbay (P. borbonia), swampbay (P. palustris), and silkbay (P. humilis). Avocado (P. americana) is now impacted in Florida, and with continued spread, laurel wilt has potential to affect avocado and native Lauraceae in California, Mexico, and throughout the American tropics. Effective lures for detection and control of X. glabratus are critical to slow the spread of laurel wilt. No pheromones are known for this species; primary attractants are volatile terpenoids emitted from host Lauraceae. This report provides a concise summary of the chemical ecology of X. glabratus, highlighting research to identify kairomones used by females for host location. It summarizes development of essential oil lures for pest detection, including discussions of the initial use of phoebe and manuka oil lures, the current cubeb oil lure, and a newly-developed distilled oil lure enriched in (-)-a-copaene.