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Why Are There Weevils in My Rice or Flour?

Written by PestMan Editorial TeamTechnical review pendingPublished Updated

Quick answer

Weevils and other small beetles in rice, flour or pasta usually came home inside the product. Rice weevils lay eggs inside individual grains, so the grain looks normal until adults emerge, while flour beetles infest milled products. Throw out infested food, clean the pantry, store grains airtight, and freeze new rice or flour for about a week to prevent repeat problems.

Why this happens

The rice weevil chews into whole grains, lays an egg and seals the hole. The larva develops hidden inside, which is why weevils can appear in a sealed bag weeks after purchase.

Flour beetles can’t attack whole grain but thrive in flour, baking mixes and cereals.

Warm temperatures and long storage times give these insects time to multiply, and they move into nearby packets.

What you may be seeing

  • Tiny dark beetles with a snout (weevils) in rice, pasta or grains.
  • Reddish-brown beetles without a snout in flour (flour beetles).
  • Holes in grains, or grey, musty-smelling flour.

What you can do

  • Throw out the infested product and check everything nearby.
  • Vacuum and wipe the pantry shelves.
  • Store rice, flour and grains in airtight hard containers.
  • Freeze new grain products for about a week before storing.
  • Buy smaller amounts and use older stock first.

What not to do

  • Do not sift out weevils and keep using heavily infested food.
  • Do not spray insecticide on food or shelves.

When professional help may be needed

Household weevil problems rarely need pest control. Businesses that store grain or flour in bulk may need a professional stored-product program.

Pantry Pests

Small moths, weevils and beetles that infest flour, rice, cereals, nuts, dried fruit, spices and pet food. They usually arrive already inside a product and spread to other packets in the pantry.

Species mentioned

Rice Weevil

Sitophilus oryzae

A tiny snouted beetle that breeds inside whole grains such as rice, wheat and pasta. Larvae develop hidden inside individual kernels.

Red Flour Beetle

Tribolium castaneum

A small reddish-brown beetle that infests flour, cake mixes, cereals and other milled products, often leaving them grey and smelly.

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Sources & further reading

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