Introgression of cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae), resistance from Sinapis alba L. to susceptible Brassica napus L. (Brassicaceae) has produced genetic lines resistant to the weevil in replicated field trials. In the current study, weevil feeding and oviposition on S. alba and on resistant novel lines developed by crossing S. alba × B. napus were less frequent than on susceptible germplasm. Development times were greater and biomass was less when larvae were reared on resistant lines or S. alba. Oocyte development was faster in post-diapause springtime adult female weevils caged on susceptible plants than in those on a resistant line, S. alba, or an early-season food host, Thlaspi arvense L (Brassicaceae). Our results suggest that antixenosis resistance and antibiosis resistance are expressed by resistant lines. These results and previous chemical analyses of these lines also suggest that resistance is potentially influenced by attractive and (or) feedings-timulant effects of 2-phenylethyl glucosinolate and antifeedant or toxic effects of 1-methoxy-3-indolylmethyl glucosinolate.