Location: Crop Bioprotection ResearchTitle: Male-produced pheromone of Spathius agrili, a parasitoid introduced for the biological control of the invasive emerald ash borer, Agrilus planipennis) Author
Submitted to: Journal of Chemical Ecology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/16/2012
Publication Date: 5/30/2012
Publication URL: http://dx.doi.org/10.1007/s10886-012-0101-2
Citation: Cosse, A.A., Petroski, R.J., Zilkowski, B.W., Vermillion, K., Lilito, J.P., Cooperband, M.F., Gould, J.R. 2012. Male-produced pheromone of Spathius agrili, a parasitoid introduced for the biological control of the invasive emerald ash borer, Agrilus planipennis. Journal of Chemical Ecology. 38(4):389-399. Interpretive Summary: Several exotic non-stinging parasitic wasps have been released in the U.S. to combat the spread of the invasive emerald ash borer beetle (EAB), currently destroying millions of ash trees in fifteen U.S. states and two Canadian provinces. Tools are needed to determine whether populations of these very small parasitic wasps are growing in numbers and thus increasing their impact in the control of EAB. One of the possible tools is the use of insect traps baited with wasp-specific attractants. The number of trapped wasps can be used to determine the population growth. This study describes the identification of a wasp-specific attractant (pheromone) and showed that this species-specific pheromone is capable of attracting one of the newly released parasitic wasps.
Technical Abstract: The braconid, Spathius agrili, has been released in the U.S. as a biocontrol agent for the invasive emerald ash borer (Agrilus planipennis), a very destructive pest of ash trees (Fraxinus spp.). We have identified and synthesized seven male-produced compounds. A flight tunnel bioassay identified three of the compounds, dodecanal, (4R,11E)-tetradecen-4-olide, and (Z)-10-heptadecen-2-one as key behavioral components. Male specificity was demonstrated by gas chromatographic comparison of male and female volatile emissions and whole body extracts. The identification was aided by coupled gas chromatographic-mass spectrometric (GC-MS) analysis, microchemical reactions, NMR, chiral GC analysis, and GC and MS comparison with authentic standards. Both the racemic and chiral forms of the '-lactone as well as both E- and Z-isomers were synthesized. Flight tunnel behavioral tests showed positive male and female S. agrili responses to both natural pheromone and synthetic blends, with upwind flight and landing on the source. Large field cage tests, using yellow sticky traps baited with pheromone, captured approximately 50% of the released male and female wasps in 24 hour periods. The identified pheromone could simplify the current detection methods of determining parasitoid establishment (the laborious task of felling and peeling ash trees for the recovery of S. agrili from infested EAB larvae), by using pheromone baited traps in the field.