Methylenedioxyphenyl Derivatives as Synergists for Carbamate Insecticides on Susceptible, DDT-, and Parathion-resistant House Flies1

Abstract

2-(2-ethoxyethoxy)ethyl 3,4-methlylenedioxyphenyl acetal of acetaldehyde (sesamex) and 3,4-methylenedioxyphenyl benzenesulfonate were found to be active synergists for four carbamate insecticides against susceptible, DDT, and parathionresistant house flies (Musca domestica L.). In contrast to the usual ratios of synergist to insecticide, in this study, insecticide/ synergist ratios higher than 1.0 were used. Cross resistance and levels of tolerance to the carbamate insecticides by DDT- and parathion-resistant flies were determined. Studies of the in vitro inhibition of human blood plasma and fly head cholinesterases have shown that with the exception of Sevin^® (1-naphthyl-N-methyl carbamate), the carbamates studied are less active inhibitors for fly head cholinesterases than for human plasma cholinesterases.