Suppressing oriental fruit fly populations with phloxine B-protein bait sprays

Abstract

The oriental fruit fly, Bactrocera dorsalis (Hendel), is a tephritid fruit fly that is a serious pest of a wide range of tropical fruits. Populations of oriental and other fruit fly species are often suppressed by utilizing aerial or ground sprays of hydrolysed protein bait mixed with malathion. Although proven to be efficacious, spraying food bait mixed with malathion in urban areas is strongly opposed by the public because of perceived public health and environmental risks. To suppress the population level of oriental fruit fly in a guava orchard in Hawaii, we used the light-activated xanthene dye, phloxine B (2′,4′,5′,7′ -tetrabromo-4,5,6,7-tetrachlorofluorescein, disodium salt), as an alternative to malathion in protein bait sprays. Because phloxine B must be ingested to be toxic, it is expected that phloxine B bait sprays will have less impact on non-target insects than the contact insecticide malathion. Evidence of suppression of oriental fruit fly population in the treatment orchard was provided by both protein bait trap catches and assessment of fruit infestation. This suppression was achieved even though there was an unsprayed guava orchard on two sides of the small (less than 2.0 ha) sprayed orchard. These results, combined with results for other fruit fly species (presented elsewhere), indicate that phloxine B-protein bait sprays can be effective in suppressing populations of several different fruit fly species and that phloxine B is a potential replacement for malathion in bait sprays for tephritid fruit fly suppression/eradication programs.