DIFFERENCES IN CYTOCHROME-P450 ACTIVITIES IN TOBACCO BUDWORM LARVAE AS INFLUENCED BY RESISTANCE TO HOST PLANT ALLELOCHEMICALS AND INDUCTION

1. Nicotine and 2-tridecanone resistant strains of the tobacco budworm, Heliothis virescens (F), had elevated cytochrome P450 content and significant increases in metabolism of five of six monooxygenase substrates relative to two susceptible strains. 2. Resistance to quercetin did not result in an increase in cytochrome P450 content; however, significant increases in metabolism were observed for two monooxygenase substrates. 3. P450 content was significantly induced by nicotine and 2-tridecanone, but not by quercetin. 4. Patterns of substrate oxidations varied between strains and inducing agents, suggesting that different isozymes of P450 are associated with resistance and induction.