resistance to multiple herbicides of differing modes of action. Bispyribac-sodium, fenoxaprop-
ethyl, and thiobencarb were used in this study as inducers and substrates of cytochrome P-
450 monooxygenases (P450s). To examine the role of P450s in herbicide metabolism by a
herbicide-resistant (R) and a herbicide-susceptible (S) late watergrass (Echinochloa
phyllopogon) biotype, seedlings were grown in absence and presence of the above three …