INSECTICIDE SUSCEPTIBILITY OF, AND METABOLISM OF DDT BY DACUS TRYONI (FROGGATT) AND DACUS CUCUMIS FRENCH (DIPTERA: TEPHRITIDAE)

The susceptibility of a strain of Dacus tryoni (Froggatt) from New South Wales and a strain of Dacus cucumis French from south‐east Queensland to the insecticides DDT, DDD, malathion, azinphos methyl and carbaryl was investigated. The available evidence suggests that these strains were susceptible to the above insecticides and therefore the data could be used as reference data should resistance in these species be suspected in the future. Both species were able to detoxify DDT to DDE with D. cucumis having a greater capability than D. tryoni. In both species penetration of C‐DDT over a post‐treatment period of 72 hr was biphasic. In the initial phase of rapid penetration, the rate of penetration followed first‐order kinetics. As the post‐treatment temperature was increased from 21 to 25 to 30°C both the rate of absorption and metabolism of DDT increased, but metabolism increased relatively more than absorption