Monday, December 10, 2007 - 10:05 AM

Potential non-target impact of the fruit fly male lure methyl eugenol in Hawaii

Luc Leblanc,, University of Hawaii, Dept. of Plant and Environmental Protection Services, 3050 Maile Way, Honolulu, HI, Roger I. Vargas,, USDA-ARS, 64 Nowelo St, Hilo, HI, and Daniel Z Rubinoff,, University of Hawaii at Manoa, Plant and Environmental Protection Sciences, 3050 Maile Way, Gilmore Hall 607A, Honolulu, HI.

Male lures are commonly used to monitor fruit flies (Tephritidae: Dacinae), and constitute a powerful control tool through mass-trapping as an alternative to the use of cover sprays. To evaluate possible attraction of non-target insects, traps baited with the male lure methyl eugenol and the female attractant Biolure were set up for 10-12 weeks and monitored weekly at 35 sites on Hawaii Island (2005) and 46 sites on Maui (2006). Trap lines covered a range of native and non-native habitats to assess the effect of habitat on non-target capture rates. Baited trap catches were compared against catches from unbaited control traps and traps artificially baited with decaying fruit flies, to isolate the effect of dead target fruit flies. Methyl eugenol attracted low but significant numbers of flower-associated insects (honeybees, Syrphidae, flower-breeding non-native Drosophilidae) and unidentified fungus gnats (Sciaridae). Saprophagous non-target insects, especially the endemic Hawaiian Drosophilidae, were abundant and diverse in Biolure traps and traps baited with decaying flies. The same species were also observed in male lure traps with large accumulations of dead trapped fruit flies. Published records of attraction to methyl eugenol, including endemic drosophilids, are now proven to be actually secondary attraction to decaying fruit flies. Endemic non-targets were collected in native and adjacent mixed forest, but almost exclusively invasive species were attracted to traps set up in non-native forests, orchards, farmlands and backyards. Based on these results, attractants may safely be used to control pest fruit flies in non-native environments given minimum distances from native habitat.

Species 1: Diptera Tephritidae Bactrocera dorsalis (Oriental fruit fly)