Cabbage Seedpod Weevil

The weevil, not native to North America, was introduced to B.C.'s lower mainland from Europe in the 1930s. From there, it spread down the coast into Washington, Idaho and Oregon. They have not been found in North Dakota.

The Life Cycle

Only one generation of weevil is produced per year. Even so, the feeding habits of both adults and larvae can have a huge impact on yield. Adult weevils overwinter under leaf litter and in shelterbelts. In April, they take flight and feed on volunteer canola and early-flowering weeds like flixweed, stinkweed, and wild mustard. Weevils are drawn to canola when the crop is in the bud to early-flower stage, where they feed on buds and pollen.

When pods are 1 cm to 2 cm in length, females lay their eggs inside the pods. These eggs hatch into larvae that feed on the seed in the developing pods. Each larvae eats about 5 seeds before reaching maturity.

Upon maturity, the larvae chew on the pod wall and then drop to the soil surface. They pupate under the soil and emerge as adults about 10 days later. When these new adults emerge in August, they begin feeding on the green pods by sticking their snout through the pod wall and sucking out new seed tissue.