FEEDING AND FORAGING OF WILD AND STERILE MEDITERRANEAN FRUIT FLIES (DIPTERA: TEPHRITIDAE) IN THE PRESENCE OF SPINOSAD BAIT

Authors: BARRY, JAMES - UNIV OF CALIFORNIA; Vargas, Roger; Miller, Neil; MORSE, JOSEPH - UNIV OF CALIFORNIA

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/2003
Publication Date: 10/30/2003
Citation: Barry, J.D., Vargas, R.I., Miller, N.W., Morse, J.G. 2003. Feeding and foraging of wild and sterile mediterranean fruit flies (diptera: tephritidae) in the presence of spinosad bait. Journal of Economic Entomology. 96(5):1405-1411.

Interpretive Summary: Malathion Bait Sprays and Sterile Insect Technique (SIT) are both used to control outbreaks of Mediterranean Fruit Flies on the U.S. mainland. GF-120, a new bait spray containing spinosad, has been developed as an alternative to traditional bait sprays containing malathion. We conducted tests on sterile and wild med flies in order to find ways to use GF-120 in conjunction with SIT. GF-120 was tested against sterile male flies and wild male and female flies to determine its effectiveness with respect to bait attraction, feeding, and kill. All fly types tested fed for the same length of time but wild flies fed more than sterile males. Flies that fed longer on fresh bait died faster. Protein-starved flies were more active and found the bait more often than protein-fed flies. We suggest that adding protein to the diet of SIT flies may decrease their response to baits, and therefore reduce mortality. This should allow SIT and bait sprays to be used together in management or eradication programs.

Technical Abstract: The sterile insect technique (SIT) is used to control wild Mediterranean fruit fly introductions in California and Florida in the USA. In the past, bait sprays containing malathion proved invaluable in treating new outbreaks or large populations prior to the use of SIT. Recently, a spinosad protein bait spray, GF-120, has been developed as a possible alternative to malathion, the standard insecticide in protein bait spray. In this study, protein-starved and protein-fed Vienna-7 (sterile, mass-reared, ¿male-only¿ strain) flies and wild males and females were evaluated to determine the effectiveness of the GF-120 protein bait containing spinosad with respect to bait attraction, feeding, and toxicology. There were no effects of diet or fly type on feeding duration in small laboratory cages. Wild flies, however, registered more feeding events than Vienna-7 males. Flies that fed longer on fresh bait died faster. Protein-starved flies were more active and found the bait more often than protein-fed flies. Data suggest that adding protein to the diet of SIT flies may decrease their response to baits, and therefore reduce mortality, and thus allow the concurrent use of SIT and bait sprays in a management or eradication program.