a-Copaene is an attractant, synergistic with quercivorol, for improved detection of Euwallacea nr. fornicatus (Coleoptera: Curculionidae: Scolytinae)

Authors: Kendra, Paul; OWENS, DAVID - Orise Fellow; Montgomery, Wayne; Narvaez, Teresa; Bauchan, Gary; Schnell, Elena; Tabanca, Nurhayat; CARRILLO, DANIEL - University Of Florida

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/30/2017
Publication Date: 6/13/2017
Citation: Kendra, P.E., Owens, D., Montgomery, W.S., Narvaez, T.I., Bauchan, G.R., Schnell, E.Q., Tabanca, N., Carrillo, D. 2017. a-Copaene is an attractant, synergistic with quercivorol, for improved detection of Euwallacea nr. fornicatus (Coleoptera: Curculionidae: Scolytinae). PLoS One. 12(6):e0179416.

Interpretive Summary: The tea shot hole borer (TSHB) is an ambrosia beetle native to Asia, where it is a pest of commercial tea. Recently, several beetles similar to TSHB have become established in Florida, California, and Israel, where they are pests of avocado. These wood-boring beetles carry a fungus that causes branch dieback disease, reducing fruit production in infected trees. Scientists from the USDA-ARS (Miami, FL), in collaboration with the University of Florida (Homestead), conducted research to evaluate the efficacy of field lures for detection of this pest. Their work identified a-copaene as a new attractant for TSHB, and a 2-component lure containing copaene and quercivorol as an improved lure for early pest detection. They also found that sticky traps were more effective than funnel traps for capture of this pest. Results of this research will benefit avocado growers in Florida and California, as well as action agencies that survey for these pests in avocado production areas.

Technical Abstract: The tea shot-hole borer, Euwallacea fornicatus Eichhoff, is an ambrosia beetle endemic to Asia and a pest of commercial tea, Camellia sinensis (L.) Kuntze. Recently, a complex of species morphologically similar to E. fornicatus has been recognized, which includes new pests established in Israel and the USA, both in California and Florida. Collectively termed E. nr. fornicatus, these cryptic species carry symbiotic Fusarium spp. fungi, some of which cause dieback disease in susceptible hosts, which include avocado, Persea americana Miller. Due to the threat to this economically important crop, research was initiated to evaluate efficacy of kairomone-based lures for detection of the beetle in Florida (termed the Florida tea shot hole borer, FL-TSHB). A series of field tests were conducted in 2016 in commercial avocado groves known to have FL-TSHB at various population levels. All tests evaluated lures containing quercivorol (p-menth-2-en-1-ol) and a-copaene, presented separately and in combination; and one test evaluated effect of trap type on beetle captures. In addition, electroantennography (EAG) was used to quantify female olfactory responses to lure emissions. This study identified (-)-a-copaene as a new attractant for FL-TSHB, equivalent in efficacy to quercivorol (the standard lure for Euwallacea detection in the USA); however, the combination of lures captured significantly more FL-TSHB than either lure alone. This combination resulted in synergistic attraction at two field sites and additive attraction at a third site. Sticky panel traps captured more FL-TSHB than comparably-baited Lindgren funnel traps. Females engaged in host-seeking flight from 11:00 to 16:00 hr (EST), with peak numbers observed between 12:00 and 13:00 hr. EAG analyses confirmed olfactory chemoreception of both kairomones, with a higher response elicited with the combination of volatiles. Results indicate that detection of pest E. nr. fornicatus in Florida can be improved by using a two-component lure consisting of p-menth-2-en-1-ol and (-)-a-copaene.