Dehydrochlorination and DDT-Resistance in Aedes aegypti

Abstract

Larvae of six DDT-resistant and five susceptible strains of the yellow-fever mosquito, Aedes aegypti (L.), were all susceptible to Dilan^® (a mixture of 1 part of 1,1-bis(p-chlorophenyl)-2-nitropropane (Prolan) and 2 parts of 1,1-bis(p-chlorophenyl)-2-nitrobutane (Bulan)), but the former were resistant to o-chloro-DDT and usually to iso-o-chloro-DDT. DMC was synergistic with DDT, o-chloro-DDT, and iso-o-chloro-DDT for the resistant strains. Paper chromatography revealed DDE as the only metabolite of DDT, other candidate metabolites and water-soluble derivatives being absent; o-chloro-DDE was detected as the only metabolite of o-chloro-DDT. The resistant strains produced more DDE and o-chloro-DDE than the susceptible strains, and this production was apparently reduced by DMC.