Abstract: The inheritance of resistance to cartap in diamondback moth Plutella xylostella (L.)is evaluated from the response of fourth instar larvae to cartap treatment. The insects used for the study are taken from laboratory reared resistant and susceptible strains. The results of genetic analysis indicate that cartap resistance　in the diamondback moth (DBM) appears to be controlled by two or more autosomal genes and the major gene(s) involved is incompletely dominant The sensitivites of cartapresistant strains to 6 insecticides have been tested The results show that the resistant strain has marked cross-resistance to dimehypo　and slight cross-resistance to DDVP and methidathion, but no cross-resistance to deltamethrin, methomyl and mipcin. The results of study on activities of AＣhE and CarE show that the resistance of the DBM larvae to cartap is not related to AChE or CarE.

Key words: Plutella xylostella(L.), cartap, insecticide resistance, genetics