Garden pest control - Pea Beetle (Description and control instructions)

Scientific name: Bruchus pisorum
Other Names: Pea Weevil, Pea Seed Beetle

The Pea Beetle or Weevil is a damaging pest to pea crops, making them unsuitable for eating and reducing germination of any which are saved for the following year. The pictures below, were taken of seed from the 'leading UK vegetable seed supplier' (their description), who have assured me that they were blast frozen to kill any pests - this might explain the appearance of the beetle.

The adults are about 4mm long with whitish spots on the wing cases (elytra). The rear section or pygidium, is whitish with two black spots.

On emerging in the spring the adults fly to the pea crop where they feed on the petals and pollen. After a few days they mate and the female lays up to 400 bright yellow eggs, singly on pods which are nearing maturity. These hatch about 10 days later and the first instar larvae which are about 1.5mm long with legs, penetrate to the seed where they moult. The second instar larvae develop for 40 to 45 days as they feed on the cotyledons and make the characteristic tunnel. Before pupation a larva will cut a circular disk (operculum) in the outer skin of the pea to allow the adult to exit when it has developed. Pupation lasts for about 10 days.

There is only one generation per year and the fully developed adult remains in the seed until the following year.