Blue stem weevil (Ceutorhynchus sulcicollis) – a potential threat to oilseed rape production

Abstract

Oilseed rape (Brassica napus) has numerous insect pests, some of which are stem-miners. Currently, blue stem weevil (Ceutorhynchus sulcicollis) is not considered a pest of oilseed rape. In the present study, a total of 60 (30 untreated, 30 insecticide-treated) oilseed rape plants were dissected; and stem-mining larvae were collected, and subsequently allowed to pupate in soil. After pupation, all emerged adult weevils were identified as either blue stem weevil (C. sulcicollis) or cabbage stem weevil (Ceutorhynchus pallidactylus). We report that under favourable conditions C. sulcicollis was capable of reaching pest status, and was significantly more abundant than C. pallidactylus, indicating a critical need for future studies regarding C. sulcicollis.