NONTARGET INSECT ATTRACTION TO METHYL EUGENOL TRAPS USED IN MALE ANNIHILATION OF THE ORIENTAL FRUIT-FLY (DIPTERA, TEPHRITIDAE) IN RIPARIAN HAWAIIAN STREAM HABITAT

This study set out to identify insect species associated with the ripa rian habitat of Hawaiian streams that were susceptible to deployment o f the plant kairomone, methyl eugenol, used in male annihilation of th e oriental fruit fly, Bactrocera dorsalis (Hendel). Six teen nontarget insect species (13 Diptera and 3 Coleoptera) were found to be attract ed to methyl eugenol traps deployed in riparian habitat in a variety o f stream ecotypes at various elevations. Only 2 Diptera attracted to t he lure, Drosophila perissopoda Hardy and D. crucigera Grimshaw (Droso philidae), were Hawaiian endemics, whereas the remainder were alien (n onnative) species. Alien drosophilids Drosophila immigrans Sturtevant and D. suzukii (Matsumura) and alien Desmometopa tarsalis Loew (Milich iidae) were the most abundant species captured in traps overall. Both plant-associated as well as carrion-associated species were captured i n methyl eugenol traps. It is suggested that the fruiting cycle of wil d guava, Psidium guajava and P. cattelianum, in mountainous and lowlan d areas of Hawaii is an important mechanism driving the population dyn amics of insects attracted to methyl eugenol traps. Host plant demogra phics and species similarities in ecological requirements are importan t factors influencing the occurrences of susceptible species between s ites. Seasonal periods of low oriental fruit fly numbers coupled with low abundances of nontarget insects create windows of opportunity duri ng which male annihilation procedures with methyl eugenol can achieve maximum effect with minimal environmental risk. Environmentally accept able use patterns for methyl eugenol can be developed through the modi fication of delivery systems and adaptation of these systems in surgic al procedures tailored to specific ecotypes. These procedures can then provide Hawaiian agriculture with badly needed farm-level or area-wid e control of destructive oriental fruit flies.