Larval survival and post-embryonic development of the spotted bollworm,Earias vittella was studied on 23 genotypes belonging to three cultivated species of cotton (Gossypium arboreum, G. bar bade use andG. hirsutum). There were significant differences in larval survival and post-embryonic development on different genotypes. The larval survival varied from 27·1 to 93·3%, developmental period from 16·6 to 20·3 days, pupation from 60 to 100% and adult emergence from 78 to 94%. Gossypol increased the post-embryonic developmental period. Majority of the larvae entered the bolls through the thallic region, possibly, to avoid higher concentrations of gossypol in the pericarpic region. Tannin content of bolls was significantly and negatively correlated with adult emergence.
Crosses between resistant and susceptible genotypes ofG. arboreum segregated into pigmented (red) and non-pigmented (green) plant types. The former were rich in gossypol and tannins compared to the latter. Gossypol and tannin content of bolls showed negative correlation with spotted bollworm incidence.