Pest Library

Pest Library

 
Picture: Bean Weevil

Bean Weevil

Acanthoscelides obtectus

Size:
1/6 of an inch

Color:
Olive brown with brown or gray spots on wing covers. Its thorax is covered with fine yellow-orange hairs.

Behavior:
The female bean weevil deposits her eggs on bean pods in the field or on whole beans in storage. Each female lays up to 60 eggs in her lifetime and numerous whitish eggs can be seen on a single bean. Bean weevils are internal feeders so the tiny, grub-like larvae bore their way into the bean. Several larvae may feed inside each bean and a considerable portion of the bean’s interior is consumed. It is the larvae that do the damage. Adults do not feed. Upon maturity, the larvae pupate near the surface of the bean and then emerge from the bean, leaving numerous holes in the bean. The entire life cycle can last from 21 days or as long as 80 days. Populations of bean weevils develop quickly in stored beans where suddenly hundreds or thousands of weevils are seen crawling or flying in infested rooms. The first indication of an infestation is often the presence of numerous flying weevils. A bag, box or storage bin of beans may be so infested that weevils are forced to leave the container in search of fresh beans on which to lay their eggs. Bean weevils “play dead” when disturbed and may take up to five minutes to resume movement.

Pantry Pests  15 types

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