Submitted to: Journal of Chemical Ecology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 4, 1996
Publication Date: N/A
Interpretive Summary: The Mexican fruit fly poses a threat to the fruit industry, especially citrus, in warm-climate regions both in the United States and abroad. It is vitally important that agricultural agencies keep watch to prevent this insect from entering areas where it does not presently occur or from breaking out into economically damaging populations in areas where it is currently under control. To do this, these agencies employ glass traps called McPhail traps containing fermenting proteinaceous baits to attract flies for the purpose of monitoring the status of fly populations. Most agree that better traps and lures are needed so that assessments of the threat can be made at an earlier stage of fly introductions or population outbreaks, thus greatly reducing the cost of managing the problem. This work is a test of a combination of two new synthetic lures for the Mexican fruit fly, each of which works in a different way to attract flies. Although each lure was attractive when tested alone, their combination was actually less effective than the more attractive of the two lures by itself. Results were disappointing, but a lesson was learned that meticulous research is still needed to gain insight into the complex relationships among attractants that work in different ways. As our understanding of this phenomenon expands, it should ultimately be possible to combine various attractants to develop new, more powerful attractant blends that can be used in traps to aid early pest detection and lower control costs.
Technical Abstract: Combinations of previously developed attractants CEHO from host fruit aroma and AMPUu from volatile metabolites of amino acids were evaluated for attractiveness to gamma-irradiated Mexican fruit flies, Anastrepha ludens, in a citrus orchard. In one experiment, McPhail traps with polyvinyl chloride (PVC) lures loaded with CEHO (10:1:1:50 mixture of 1,8-cineole, ethyl hexanoate, hexanol and ethyl octanoate) were more attractive than blank traps. McPhail traps with AMPu (10:10:1 mixture of ammonium bicarbonate, methylamine HCI and putrescine) were more attractive than blank and CEHO traps. Traps containing both AMPu and CEHO lures were less attractive than traps containing AMPu alone. In another experiment, sticky yellow panels and spheres were used to compare attractiveness of the same two attractants in different formulations. Sticky traps baited with membrane formulations of CEHO (10:1:1:10 mixture of the chemicals listed above) were not significantly attractive. Sticky traps with polypropylene tubes containing an agar formulation of AMPu were more attractive than blank and CEHO baited traps. As in the first experiment, traps with both AMPu and CEHO lures were less attractive than traps with AMPu alone. Results indicate that attractive host-odor volatiles and attractive amino-acid metabolites interact negatively with regard to attractiveness to the Mexican fruit fly.