ARS | Publication request: Identification, Synthesis, and Field Evaluation of the Sex Pheromone from the Citrus Leafminer, Phyllocnistis citrella

Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 1, 2005
Publication Date: January 6, 2006
Citation: Leal, W.S., Parra-Pedrazzoli, A.L., Cosse, A.A., Murata, Y., Bento, J.S., Vilela, E.F. 2006. Identification, Synthesis, and Field Evaluation of the Sex Pheromone from the Citrus Leafminer, Phyllocnistis citrella. Journal of Chemical Ecology. 32(1):155-168

Interpretive Summary: Attractants for the citrus leafminer moth, Phyllocnistis citrella, are sorely needed not only for monitoring and controlling populations, but also for quarantine purposes as this serious pest of citrus is spreading rapidly. Phyllocnistis citrella was originally described from Calcutta, India, from where it spread to Australia, Japan, Taiwan, Middle East, and Africa; it is now established in five continents. In less than a decade, the citrus leafminer spread through Florida, Alabama, Louisiana, Texas, Brazil, and most Latin American countries and has reached California, Mexico, and Hawaii. Earlier reports showed that Japanese populations of the citrus leafminer could be captured in traps baited with a compound called (Z,Z)-7,11-hexadecadienal. Subsequent experiments, however, failed to catch males of P. citrella in traps baited with this compound in field tests in China, Italy, Spain, the USA, Turkey, and Brazil. The results of this study describe the isolation, identification, synthesis, and field evaluation of the sex pheromone of the Brazilian population of the citrus leafminer. This pheromone could become a useful tool in monitoring the presence of populations of the citrus leafminer.

Technical Abstract: Using male antenna as the sensing element, three EAD-active peaks were identified from gland extracts of the citrus leafminer, Phyllocnistis citrella. Based on GC-MS and GC-IR data, the semiochemicals were identified as a novel pheromone, (Z,Z,E)-7,11,13-hexadecatrienal, a previously identified attractant, (Z,Z)-7,11-hexadecadienal, and (Z)-7-hexadecenal in a ratio of 30:10:1, respectively. Identification was confirmed with synthetic compounds, which gave retention times identical to those of the natural products in three capillary columns with polar and non-polar phases. While traps baited only with the previously identified attractant alone did not catch any males in Brazil, binary and tertiary mixtures with the major constituents caught significantly more male moths than traps baited with five virgin females.