How to Kill Flour Insects

How to Kill Flour Insects. Flour beetles, grain beetles, meal moths, and weevils are all types of insects that infest flour and grain items. They find their way into bags of dry food and proceed to lay eggs. This is a survival mechanism for the insects: once hatched, the larvae will have instant access to food. Also, because these insects prefer a humid environment, houses are the perfect environment for reproduction since we tend to keep our homes warm.

Eliminate insects that make their way into your flour.

Things Needed

  • Flour sifter
  • Clean plastic container
  • Cleaning agents
  • Air-tight container

Step 1

Sift the flour from the bag. Place the sifted flour in a clean plastic container.

Step 2

Place the container in the freezer for a week. The eggs cannot thrive in cold temperatures and will die.

Step 3

Clean out your cupboard shelves thoroughly while the flour is in the freezer. Use cleaning agents to disinfect the area, and take a vacuum to eliminate crumbs in the corners and crevices.

Step 4

Remove the container from the freezer after a week. Place the container in your clean cupboard for a few days to thaw.

Step 5

Repeat steps two and four. This will kill any eggs that survived the first freezing.

Step 6

Sift the flour again and place it in an air-tight container. Place the container in your clean cupboard.


  • Keep all your dry foods in air-tight containers. If left unchecked, weevils will move to different types of food such as cereal, rice, and pasta.
  • Sprinkle bay leaves in your disinfected cupboards. Weevils do not like the scent of bay leaves, so they will not venture around your cupboards if they smell the herb.
  • You may also place small boxes of matches around your disinfected cupboards. Weevils do not like the scent of sulfur, so they will not crawl around your cupboards if they smell the matches.
  • Even if you miss a few weevil eggs after freezing and sifting your flour, the bugs are not harmful. Although it may seem unsanitary, thoroughly cooking the flour will also cook the bugs, making them a mini source of protein.


  • UNL Extension in Lancaster County: Insects, Spiders, Mice, and More
  • NDSU: Bugs in Your Cupboard
  • Utah State University Extension: Extension Entomology