Cabbage seedpod weevil

Taxonomic position: The Cabbage seedpod weevil (Ceutorhynchus obstrictus) belongs to the order Coleoptera and the family Curculionidae (true weevils). It is recognized as a significant agricultural pest, specifically adapted to exploit the reproductive structures of brassicaceous plants.

Host crops: This pest primarily infests oilseed rape (canola), mustard, cabbage, radish, and other members of the Brassicaceae family. It is a major economic concern in commercial agriculture, capable of causing yield reductions if left unmonitored during the sensitive reproductive stages of the host plants.

Biology and life cycle: Adult weevils overwinter in debris or soil. As temperatures rise in spring, they migrate to host crops. Females use their rostrum to pierce young pods and deposit eggs inside. The larvae develop inside the seedpod, feeding on the seeds. Once mature, larvae exit by chewing through the pod wall and drop to the soil to pupate.

Nature of damage and impact: Economic damage is caused by the larvae feeding on the developing seeds within the pods. Furthermore, the exit holes created by the larvae serve as entry points for moisture and secondary pathogens, such as Alternaria species, which can cause pods to shatter prematurely and lead to significant harvest losses.

• Rotate crops to break the life cycle, avoiding adjacent fields of brassicas.
• Use yellow sticky traps to monitor adult weevil populations during flowering.
• Apply insecticides during the bud stage if economic thresholds are exceeded.
• Promote natural biological control agents and maintain diverse field margins.