Negatively Correlated Cross-Resistance between N-Methyl Carbamate and Monocrotophos in Green Rice Leafhopper, Nephotettix cincticeps Uhler

Abstract

Although monocrotophos showed strong inhibition to N-methyl carbamate resistant acetylcholinesterase in the green rice leafhopper, Nephotettix cincticeps, the toxicity was not so high to Nakagawara populations of the leafhopper. The different results between in vitro and in vivo experiments were thought to be caused by an increase of aliesterase activity in Nakagawara strains which are resistant to both organophosphorus insecticides and N-methyl carbamates. Thus, MC-R strain which has only N-methyl carbamate resistance gene was bred by introducing N-methyl carbamate resistance gene of Nakagawara-3-C strain to susceptible Shiraoka strain. Then monocrotophos showed negatively correlated cross resistance against N-methyl carbamates in Shiraoka and MC-R strains under both in vitro and in vivo conditions.