Cabbage Seedpod Weevil

The Cabbage Seedpod Weevil is an insect that is causing damage to canola crops in southern Alberta and therefore should be on our watch-list for the County. Although the weevil has been found mainly in the southernmost part of the province it has been moving north in the last two years. Hopefully we never have to deal with this insect, but with our changing climate, anything is possible. The Seedpod Weevil produces one generation per year and overwinters in roadside ditches, fence lines and tree litter.  The adult female makes a hole in the canola pod and lays her eggs directly into the pod. The eggs hatch producing larvae that feed on the growing seed within the pod. Depending on the degree of infestation the resulting yield loss can be significant.

What To Look For

Feeding larvae
Adult weevil Adult weevil

Prevention

The fact that the Cabbage Seedpod Weevil is capable of inflicting serious damage to canola crops, means we need to be diligent and proactive in preventing this insect from establishing in the County. Some of the things that can be done to help stave off establishment are:

  • Monitor possible migration northward by checking the provincial forecast maps
  • Control all cruciferous plants that may act as hosts to the weevil (i.e. volunteer canola, stinkweed, etc.)
  • Scout fields in the fall if there are any suspicions that this insect may be present
  • Apply registered insecticide at recommended timing and at label rates
  • Insecticides should be used only when target thresholds are reached to prevent unnecessary injury to beneficial insects