Development of bait stations for fruit fly population suppression

The application of insecticides is an essential component for eradication or management of fruit fly pests. Impact on nontarget organisms and public rejection of areawide pesticide applications have been major concerns in managing these programs. Bait stations have been proposed as alternative treatments in areas where broadcast insecticides are not acceptable. In this study, we defined bait stations as discrete containers of attractants and toxins, which are targeted at specific pests. Tests were carried out using the Mexican fruit fly, Anastrepha ludens (Loew), as the experimental insect. Our first bait station design was a sheet of sponge material fastened to a plastic peaked cover. Liquid bait consisting of protein hydrolyzate, sugar, adjuvants, a photoactive dye toxicant, and other additives was applied to the sponge. This station, when tested in an orchard, reduced sterile released adult populations by 70-90% in 4 d compared with check plots. Other tests in field cages showed that the bait station was approximately 22% less effective in killing adults compared with spot sprays on trees. We formulated a gelled bait by using a more refined hydrolyzed protein, supplemental attractants, feeding stimulants, and additives to protect the bait from drying. A series of experiments were carried out in field cages by using a cylindrical bait station that provided improved protection of the bait. These tests showed that there is a gradual decline in bait effectiveness with age.