Morphology of the pre-imaginal life stages of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera : Curculionidae)

摘要

The cabbage seedpod weevil is a serious pest of canola or oilseed rape (Brassica napus L.) and several other brassicaceous seed crops in both Europe and North America. A number of Ceutorhynchinae species can occur in canola or in cruciferous weeds infesting the crop, but immature stages of few of the species are well described. The morphology of pre-imaginal life stages of the cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham), is presented. Descriptions are given of taxonomic characters observed under both phase contrast and scanning electron microscopy. Characters to separate C. obstrictus and its sympatric congener Ceutorhynchus neglectus Blatchley include the numbers of dorsal, ventral, and lateral epicranial setae and the numbers of setae on the labrum, maxillary palps, stipes, and mala.