Location: Functional Foods ResearchTitle: Field test for repellency of cedarwood oil and cedrol to little fire ants
Submitted to: Hawaiian Entomological Society Proceedings
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/18/2015
Publication Date: 12/1/2015
Publication URL: http://handle.nal.usda.gov/10113/5203492
Citation: Eller, F.J., Fezza, T., Carvalho, L.A., Jang, E.B., Palmquist, D.E. 2015. Field test for repellency of cedarwood oil and cedrol to little fire ants. Proceedings of the Hawaiian Entomological Society. 47:71-77.
Interpretive Summary: This research determined that extracts of Eastern red cedar (Juniperus virginiana L.) (Cupresseaceae) were repellent to the little fire ant (LFA), Wasmannia auropunctata Roger in a field test in Hawaii. The LFA is a very serious invasive pest and new methods for controlling this species are needed. Eastern red cedar is an abundant renewable resource and represents a vast potential source of valuable natural products that may serve as natural biocides. The wood from Eastern red cedar was extracted using supercritical carbon dioxide to give cedarwood oil (CWO). Cedrol, the most abundant component of CWO, was tested as well. In a macadamia orchard known to have LFA present, chopsticks baited with peanut butter were used to test the repellency of CWO and cedrol. The chopsticks were collected after ca. 24 hours and the number of LFAs present determined. The control chopsticks had very high numbers of ants present. The CWO-treated chopsticks had significantly fewer ants than did the control chopsticks while the cedrol-treated chopsticks were slightly repellent to the ants. These results demonstrate that CWO could be used as a safe natural ant repellent from a renewable source and could help manage the LFA.
Technical Abstract: Eastern red cedars (ERC) (Juniperus virginiana L.) are an abundant renewable resource and represent a vast potential source of valuable natural products that may serve as natural biocides. The aromatic wood can be extracted to obtain cedarwood oil (CWO) and critical carbon dioxide (CO2) extraction of ERC gives both high yields and high quality CWO. CO2-derived CWO and cedrol, the most abundant component of CWO, were field-tested for repellency against the little fire ant (LFA), Wasmannia auropunctata Roger, in a Hawaiian macadamia orchard. Field tests were conducted using chopsticks baited with peanut-butter placed in established LFA trails on macadamia tree trunks and branches. The chopsticks and any ants present were collected after ca. 24 hours and the number of ants determined by visual counting. Four treatments were compared: Hexane only control; mineral oil; CWO; and cedrol. Control chopsticks and chopsticks treated with mineral oil had very high numbers of ants and were statistically equivalent. The CWO-treated chopsticks had significantly fewer LFAs than all the other treatments. Chopsticks treated with cedrol were somewhat repellent, but significantly less repellent than chopsticks treated with CWO. This research suggests that CWO extracts from J. virginianna may provide a renewable source of a safe natural ant repellent and could help manage this invasive pest.