The difference in host selection between the polyphagous Helicoverpa armigera(H bner)and the oligophagous H.as-sulta Quen e was examined,with cotton(Gossypium hirsutum),tomato(Lycopersicon esculentum)(hosts of H.armigera),tobacco(Nicotiana tobaccum)(host of both H.armigera and H.assulta),and bush redpepper(Capsicum frutescens)(host of H.assulta)as testing plants.A multiple-choice test was used with caged plant cuttings for adult oviposition and with leaf discs for larval feeding.A no-choice test was run for evaluating larval growth rate.The results indicated that the relationship between larval performance and adult pref-erence of H.assulta was more conspicuous than that of H.armigera.Reciprocal hybridization between H.armigera and H.assulta followed by backcrossing of the hybrids(F 1 )with H.armigera was also carried out for genetic study on host selection of these two insect species.A two-choice test with cotton and bush redpepper leaf discs showed that H.armigera larvae preferred to feed on cotton,and H.assulta larvae to bush redpepper;feeding preferences of the two F 1 lines were intermediate between those of their parents,but close to that of their female parent;preference indexes of backcross lines also showed that both maternal factor and chromosomal inheritance were involved in feeding selection of two Helicoverpa species. The difference in host selection between the polyphagous Helicoverpa armigera (H bner) and the oligophagous H. as-sulta Quen e was examined, with cotton (Gossypium hirsutum), tomato (Lycopersicon esculentum) (hosts of H. armigera), tobacco (Nicotiana tobaccum (host of both H. armigera and H. assulta), and bush redpepper (Capsicum frutescens) (host of H. assulta) as testing plants. A multiple-choice test was used with caged plant cuttings for adult oviposition and with leaf discs for larval feeding. A no-choice test was run for evaluating larval growth rate. The results indicated that the relationship between larval performance and adult pref-erence of H. assulta was more conspicuous than that of H. armigera. Reciprocal hybridization between H .armigera and H.assulta followed by backcrossing of the hybrids (F 1) with H.armigera was also carried out for genetic study on host selection of these two insect species. A two-choice test with cotton and bush redpepper leaf discs showed that H.armigera larvae preferred to feed on cotton, and H.assulta larvae to bush redpepper; feeding preferences of the two F 1 lines were intermediate between those of their parents, but close to that of their female parent; preference indexes of backcross lines also showed that both maternal factor and chromosomal inheritance were involved in feeding selection of two Helicoverpa species.