DEVELOPMENT OF BAIT STATIONS FOR FRUIT FLY POPULATION SUPPRESSION

Authors: Mangan, Robert; MORENO, DANIEL - FORMER ARS EMPLOYEE

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2006
Publication Date: 4/2/2007
Citation: Mangan, R.L., Moreno, D.S. 2007. Development of bait stations for fruit fly population suppression. Journal of Economic Entomology. 100:440-450.

Interpretive Summary: Programs to manage or eradicate fruit flies are dependant on application of insecticides to reduce pest populations and protect fruit from infestation. Programs to eradicate fruit flies depend on reducing the pest population to a degree that sterile insects or killing all males by use of specific attractants can be effective. In many areas, public opinion, health considerations, organic crop production, or other factors forbid the use of insecticide sprays. In this study, we developed and tested discrete stations that contain the toxic bait and avoid its introduction into the environment. We tested bait and insecticide mixtures that contained much lower concentrations of safer insecticides which were thousands of times less toxic than the commonly used malathion broadcast baits. We developed a gelled bait that emits odors that attract the flies to the station and contains feeding stimulants to induce the flies to feed on the bait. The station design allows the insect to leave the station, and we showed that these insects survive long enough to transfer the toxic bait to other flies as part of their courtship behavior. The bait gel was shown to be effective in stations for 16 weeks under Texas orchard conditions. Evidence of effectiveness of the station with this bait indicated that populations could be reduced by more than 90% during the maturation period of fruit flies.

Technical Abstract: The application of insecticides is an essential component for eradication or management of fruit fly pests. An impact on non-target organism and public rejection of area-wide pesticide application has been a major problem in managing these programs. Bait stations, which are discrete containers of attractants and toxins, have been proposed as alternative treatments in areas where broadcast insecticides are not acceptable. We extended this definition to require that pesticide formulations in the stations have low toxicity to humans or contact or ingestion. We achieved this requirement by using insecticides that have lower mammalian toxicity than the carbamates and organophos- phates commonly used in sprays and using low concentrations of insecticides in baits that must be consumed by the fruit flies. 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 days compared to check plots. Other tests in field cages showed that the bait station was about 22% less effective in killing adults compared to spot sprays on trees. Field cage tests also showed that the bait degenerated in about 4 weeks, the insecticide did not lose toxicity, and kill rate could be restored by addition of attractant supplements. We formulated a gelled bait 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 using a cylindrical bait station that provided improved protection of the bait. Longevity of the gelled bait in a commercial model of the bait station was tested by hanging the stations in our orchard, then testing baits of various field exposure ages in the field cage. These tests showed that there is a gradual decline in bait effectiveness with age. The average adult survival during the four day test was 27% for baits aged 1 to 278 days. Under field conditions with 12-15 day maturation time, the expected survival of females to maturity would be about 8%.