Cabbage seedpod weevil (Coleoptera: Curculionidae): new pest of canola in northeastern North America

Abstract

The cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) [= C. assimilis (Paykull)] (Colonnelli 1993), is a univoltine species native to Europe that feeds on canola and other oilseed cruciferous plants. The adult overwinters in debris and soil outside fields and colonizes canola at the blooming stage (Dosdall et al. 2001). Eggs are laid singly into the immature pods and each larva consumes five to seven seeds before cutting a hole in the pod to wriggle out and pupate in the soil (Dmoch 1965). Yield losses are difficult to assess because the plant compensates for bud and pod injuries caused by insects or pathogens (Lamb 1989). Nevertheless, pod feeding by larvae causes much damage, as canola yields can be reduced from 15 to 35% (Homan and McCaffrey 1993). Feeding by adults can also be significant, as it can reduce oil content, seed weight, and seed germination (Buntin et al. 1995).