Comparative effectiveness of avermectins and deltamethrin in suppressing oviposition in Lucilia cuprina (Diptera: Calliphoridae).

The activities of three avermectins and deltamethrin as oviposition suppressants were investigated with a laboratory bioassay in which gravid females of the blowfly Lucilia cuprina (Wiedemann) were exposed to treated oviposition targets. An easily comparable index of suppression, the oviposition suppression concentration (OSC), was defined. All four compounds were effective oviposition suppressants. The three avermectins had similar OSC50 values (approximately 13 ppm). Deltamethrin, with an OSC50 of 0.4 ppm, was the most potent suppressant. The avermectins all produced significant mortality in adults with suppressed oviposition, while deltamethrin did not cause an increase in deaths at concentrations giving up to 100% suppression of oviposition. The toxicities of all four compounds to adult females were similar when assessed by topical application.