The cabbage webworm, Hellula undalis (Fabricius) (Lepidoptera: Pyralidae) is a serious insect-pest on brassicas and other crucifers. Previous study has indicated that biology of H. undalis depends on host plant. The development time and survival rate of immature stages, longevity and fecundity of the cabbage webworm were investigated on three cultivars of brassica such as Indian mustard (Brassica juncea), leaf mustard (Brassica integrifolia) and pak choi (Brassica rapa chinensis). Developmental time from first instar larva to adult and life cycle of the webworm reared with pak choi were longer than those with leaf mustard and India mustard. Longevity and fecundity of the adults on pak choi were lower than those on leaf mustard and India mustard. The results indictated that pak choi was the less suitable host plant followed by leaf mustard and Indian mustard. Thus, the development of resistance plant cultivars should be intended as an integrated pest management measure in the control of H. undalis.