Multiple insect resistance has been detected in the soybean lines PI 171,451, PI 227,687 and PI 229,358 (Van Duyn et al., 1971; Clark et al., 1972; Hatchett et al., 1976). In particular Hatchett et al. (1976) demonstrated resistance to Heliothis zea and Heliothis virescens in all three lines. On the basis of percentage larval mortality, PI 171,451 and PI 229,358 were more resistant to H. zea than H. virescens, while PI 227,687 was equally resistant to both species and also showed superior levels of resistance.