Pest profile

Bean Weevil

Acanthoscelides obtectus · Coleoptera: Chrysomelidae[5]

The bean weevil is a small seed beetle, not a true weevil, whose larvae live inside dry beans and related seeds. Infestations can start in the garden and continue in storage, where the beetles breed continuously in warm pantries.[1][2][3]

Adult bean weevil, a small olive-brown beetle mottled with darker and lighter bands and reddish legs and antennae, on a white surface
Adult bean weevil, a small olive-brown beetle mottled with darker and lighter bands and reddish legs and antennae, on a white surface. (c) E. A., some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Adults are about 1/8 inch long, olive brown mottled with dark brown, gray or cream markings, with reddish legs and antennae.[1][2]
  • The body is somewhat teardrop-shaped and narrows evenly toward a small head.[3][2]
  • The hind thigh carries one large and two small spines, visible with a hand lens.[1]
  • The surest sign is beans with neat round holes where adults have emerged; several larvae may develop in one bean.[1][3]

Look-alikes

Look-alikeHow to tell them apart
Granary weevilA true weevil with a distinct snout that develops inside whole grain kernels; the bean weevil isn't a true weevil and develops in legume seeds.[4][1]
Rice weevilAnother snouted grain weevil that attacks whole grain rather than dry beans and peas.[4][1]
Cowpea weevilA related bean pest whose wing covers are tipped with black and carry two large black dots.[2]

Where it lives

The bean weevil occurs throughout the United States, infesting legumes both in the field and in storage.[1]

Biology and life cycle

Females lay an average of 75 eggs, singly or in clusters near beans, or loosely among stored beans and through cracks in pods.[1][3]

Larvae and pupae develop inside the bean, and adults chew out through a round hole in the seed coat.[3][1]

The life cycle takes 21 to 80 days, and indoors the beetles breed continuously in dried legumes kept warm.[1][2]

Adults are strong fliers and don't feed on the legume seeds.[2][1]

Damage and signs

  • Larvae feeding inside can consume nearly the entire contents of a bean.[3]
  • Infested stock includes dried beans, cowpeas, lentils and peas; damage is a mix of feeding and contamination.[2][3]

Health risk

The concern is food loss: larvae hollow out beans and contaminate stored legumes, which are best thrown out once infested.[3][2]

Control

Prevention

Keep food storage areas dry with good ventilation, and check stored legumes regularly.[2]

In the garden, plant weevil-free seed and remove and destroy bean plants right after harvest; insecticide treatment isn't recommended.[3]

Keep them out

Inspect incoming beans for beetles and store all susceptible foods in pest-proof containers.[2]

Sanitation

Find and dispose of infested legumes, clean up spills and storage areas, and keep legumes in regular rotation.[2]

Common questions

Where did the little beetles in my dry beans come from?
Bean weevil infestations can start in the field or garden before harvest, then keep breeding in storage.[1][3]
Should I spray my pantry for bean weevils?
No. Throw out infested legumes, clean the storage area and keep beans in sealed containers; insecticides aren't recommended.[2][3]

Sources

  1. University of Florida, Department of Entomology and Nematology, “Bean weevil, Acanthoscelides obtectus (stored product pests image gallery).” entnemdept.ufl.edu/projex/gallery/dl/stored_product_pests/text/bean_weevil.htm (accessed 2026-10-06)
  2. Utah State University Extension, Integrated Pest Management, “Bean and Cowpea Weevils (Nuisance Pests).” extension.usu.edu/planthealth/ipm/notes_nuisance/bean-cowpea-weevils (accessed 2026-10-06)
  3. University of California Statewide IPM Program, “Bean Weevils (Home and Landscape).” ipm.ucanr.edu/home-and-landscape/bean-weevils/ (accessed 2026-10-06)
  4. Purdue University Extension Entomology, “E-237: Rice, Granary, and Maize Weevils (November 2018).” www.extension.entm.purdue.edu/publications/E-237/E-237.html (accessed 2026-10-06)
  5. iNaturalist, “Acanthoscelides obtectus taxon page (order and family).” www.inaturalist.org/taxa/212223 (accessed 2026-10-06)

Updated 2026-10-06. Built from sourced records. Spot an error? Tell us.