Abstract: The mode of inheritance of resistance to fenvalerate in cotton bollworm, Hellcoverpa armigera(Htibner), was evaluated from log dosage-probit mortality curves constructed from the response of third instar larvae to fenvalerate treatment.The insects ased for the study were taken from laboratory reared susceptible and resistant strains; the resistant strain exhibited over 2000-fold resistance to fenvalerate as compared with the susceptible strain. The results of genetic analysis indicated that fenvalerate resistance in cotton bollworm appeared to be controlled by two or more autosomal genes and the major gene (s) involved was incompletely dominant. Synergism of PBO revealed that MFO was mainly responsible for the resistace, so the MFO gene was incompletely dominant.

Key words: Helicoverpa armigera (Hiibner), fenvalerate, resistance inberitance, incomplete dominantce, MFO gene