Cabbage seedpod weevil

Adults. The adults overwinter beneath leaf litter in tree shelterbelts, roadside ditches and woodlots. During September to early November, they select overwintering sites and burrow beneath the soil surface where they are protected from low temperatures. In the spring, the adults emerge over a period of several weeks, and peak emergence occurs when soil temperatures reach 15 C. Adults seek out early flowering brassicaceous weeds and are especially attracted to stands of wild mustard (Sinapis arvensis L.) and volunteer canola. Adult weevils have ash-grey elytra (wing covers) as well as ash-grey abdomens and are approximately 3 to 4 mm long. They have a prominent curved snout that is typical of most weevils. The adults move to canola crops in June when the crop is in the bud to early flowering stages. They feed on canola pollen, nectar, buds and racemes. The adults may concentrate along field edges before spreading out more uniformly across the canola field. When disturbed, the adults often drop to the ground and “play dead.” After several seconds, they resume activity. Mating occurs from spring to early pod development, usually on a host plant. The majority of eggs are laid shortly after flowering. The female lays the eggs inside the developing pod.
Eggs. Eggs are very small, oval and opaque white. Most often, only a single egg is deposited per pod; however, two or more eggs can be laid per pod during outbreaks. Eggs hatch in about six or seven days, and females continue to lay eggs until they die later in the season.
Larvae. Larvae are white and grub-like, without legs or eyes. Soon after hatching, the larvae begin feeding within the pods on developing seeds. Larval development takes approximately six weeks, and during this time, a single larva consumes five to six canola seeds. There are three larval stages (instars).
Pupae. Mature larvae chew small, circular exit holes in the pod walls, drop to the ground, burrow in and pupate within earthen cells. New generation adults emerge about 14 days later and feed on immature canola or other green cruciferous plants until late in the season when they enter overwintering sites.