Abstract: Continuously selected with phoxim for 12 generations at the average survival percentage of 37.6%, the strain of Helicoverpa armigera, collected from Dongtai County, Jiangsu Province, had a 4.9-fold increase in resistance to phoxim. Based on the method described by Tabashnik(1992), the realized heritability (h²) of resistance to phoxim in H．armigera was estimated to be 0.0865. The rate of resistance development in the cotton bollworm was predicted based on the estimation of the realized heritability (h²). Resistance risk assessment, factors affecting the resistance development and resistance management were discussed.

Key words: Helicoverpa armigera, phoxim, realized heritability, resistance risk assessment