The effects of two insect growth regulators on the biting midges, Culicoides circumscriptus Kieffer (Diptera : Ceratopogonidae)

Abstract

Growth-inhibiting effects of two kinds of insect growth regulators (IGR), Altosid 10F (methoprene 10% slow release formulation) and Dimilin (diflubenzuron 25% wettable powder) were evaluated against the last instar larvae of Culicoides circumscriptus Kieffer in the laboratory conditions. Growth-inhibiting effects of these two IGRs were observed as the larval death (including the failure of pupation), the pupal death, the failure of emergence and the deformed adult. Significant differences were found in physiological activities of these two compounds. The effects of Altosid 10F mainly resulted in the death of pupae at higher concentrations and in the deformed adults at lower concentrations, while Dimilin inhibited the pupation. IC_<50> values of Altosid 10F and Dimilin against the last instar larvae of C. circumscriptus were 0.0094ppm and 0.0052ppm, respectively. It was proved that both Altosid 10F and Dimilin shows the high growth-inhibiting effects on C. circumscriptus.