Cowpea Weevil

Family Name

Callosobruchus maculatus

Characteristics

Type:

Crawling – Flying

Size:

About 0.16 inches long.

Colour:

Brownish in colour; some specimens may appear greenish brown in colour.

Behaviour:

Cowpea weevils are comprised of several species. The life cycle is similar to that of bean weevils. Like bean weevils, the cowpea weevil is an internal feeder. The female deposits her eggs on the outside of the bean. The larvae bore into the bean and several larvae infest the same bean. Upon maturity, the larvae pupate near the surface of the bean and then emerge from the bean leaving numerous holes in the bean. Huge populations can quickly develop especially under ideal conditions of 90ºF and 90% humidity. The first indication of an infestation is often the presence of numerous flying weevils. Usually, the infested bag, box or storage bin of cowpeas or other beans is so infested that weevils are forced to leave the container in search of fresh beans on which to lay their eggs. Cowpea weevils “play dead” when disturbed and may take up to five minutes to resume movement.

Habitats

These weevils develop best in cowpeas (black-eyed peas), but may develop in a few other types of beans, such as chick-peas and lentil beans. They do not infest other types of stored foods such as cereals or whole grains.

Tips for Control

The control of any stored product pest involves many steps, primary of which is discovery of infested food items or other sources of infestation (e.g., food spillage accumulation). When cowpea weevils are present, all items containing or made of cowpeas or other whole beans need to be examined.

Consider the following actions to prevent an infestation:

 Discard infested cowpeas/beans in outdoor trash.
 Freeze any suspect items at zero degrees Fahrenheit for six days.
 Clean cabinets and shelves where infested cowpeas/beans are stored by vacuuming and using soap and water.
 Store all dried cowpeas/beans should be stored in a glass or plastic container with a tight lid. This will at least keep a potential infestation contained.