The use of sterile males to control populations of Queensland fruit fly Dracus tryoni (Frogg) (Diptera : Tephritidae) I. methods of mass rearing, transporting, irradating and releasing sterile flies

Abstract

This paper describes the methods devised and used in rearing, transporting, sterilizing, and releasing Dacus tryoni for field experiments aimed at controlling natural populations of this pest with sterile males. The general principles of economical mass-rearing, including the management of breeding stocks, and quality and economy in larval rearing, and previous work on mass-rearing Dacus tryoni are discussed. Adults required exposure either to natural or artificial dusk to stimulate mating, 120 cages each stocked with 4000-5000 flies provided sufficient eggs to achieve a production rate of up to l0*6 pupae per week; eggs were collected in apple-hollows; larvae were reared in a medium whose basic components were yeast and dried powdered carrot; pupae were stored at 25ºC and 70-80% R.H. until they were ready for irradiation; they were irradiated on the eighth day of pupal life using a 60Co source to produce doses between 6000 and 10,000 rads. After they had been irradiated the pupae were consigned by commercial aircraft to country airports near the points of release. The sites of release were trees; a release platform protected the pupae from rain, sun, and predators.