Southern cowpea weevil
Callosobruchus chinensis (L.)

Classification

Primary pest; Grain feeder
Order: Coleoptera
Family: Chrysomelidae
Acronym: CCH

Description

  • Adults are small (3 to 4 mm long), globular body with long legs and long antennae.
  • Elytra are patterned and the last abdominal terga is exposed.
  • Larvae are white and grub-like with reduced legs.

Similar species

Commodities affected

  • Chick peas, lentils, garden peas, mung beans

Signs of infestation

  • Emergence holes from seed are obvious and characteristic.

Damage

  • Damage is distinctive. When adults emerge from a seed, they leave a neat circular exit hole.
  • Heavy infestation can cause commodity to heat, resulting in a loss of quality and mould growth.

How to control

Geographic range

  • Is abundant in the tropics
  • Has been recorded from Saskatchewan, Manitoba, Ontario in Canada

Where found

  • Is occasionally found in beans imported to Canada
  • Is a pest of stored beans, peas and wild legumes
  • Attacks field beans and peas in the field
  • Can be a storage pest in granaries where it will breed continuously on dried pulses
  • Requires high temperature and moderate relative humidity to reproduce well, so does not do well in Canada

Life history

  • Adults are very active and will run and fly readily.
  • Females lay eggs by attaching to the outside of the seedcoat.
  • Larvae feed and develop within the seed.
  • Prior to pupation, the larvae chews an exit hole for the adult to emerge from.

Video of Southern cowpea weevil

Transcript

Three adult southern cowpea weevils move across yellow peas. Some of the peas have the neat, circular exit hole left when the adults emerge from the pea after developing inside of it.