The combinative rate measurement of (3-[I125] iodotyrosyl) α-bungarotoxin was applied in the analysis of the relationbetween nerve acetylcholine receptor and three types of insecticide resistance in diamondback moth, Plutella xylostella(L.). In the dimehypo-resistant strain and in the cartap-resistant strain, the nerve acetylcholine receptor showed theremarkable insensitivity to dimehypo and cartap, of which the binding rate to ligand was approximately 66 and 60%,respectively, of the susceptible strain. The sensitivity to deltamethrin in the deltamethrin-resistant strain did not showvisible change. These results indicated that the decline in the sensitivity of nerve acetylcholine receptor to insecticidemight be a potential mechanism to nereistoxin insecticides resistance in the diamondback moth.
