- Scientific name
- Tribolium castaneum
- Also called
- flour bug, confused flour beetle (close relative)
- Size
- About 1/8–3/16 in
- Color
- Reddish brown, shiny
- Found in
- Flour, baking mixes, cereal, crackers, dry pet food
- Harmful?
- Spoils food; not a health risk
- Active
- Year-round indoors
What to do
Red flour beetles and their close relative, the confused flour beetle, are the “flour bugs” found in old bags of flour and baking mixes. They can’t chew into whole grains, so they live in milled and broken products. They don’t bite. The one thing to do: throw out the infested flour or mix and store the rest in containers with tight lids.
This page covers how to identify flour beetles, tell them from other pantry beetles and keep them out. It rests on University of Kentucky and UC IPM guidance.
How to Identify a Flour Beetle: Flat, Shiny, Reddish Brown
- About 1/8 to 3/16 inch, long, flat and shiny reddish brown.
- No snout, unlike weevils.
- Antennae that end in a small club. In the red flour beetle the last three segments widen suddenly; in the confused flour beetle they widen gradually (UC IPM).
- Larvae: slender, pale yellow-white worms with two small points at the tail.
Flour beetles on the rim of a food container. Each one is only about ⅛ inch long. Photo: Ranjha333 (CC0), via Wikimedia Commons.
Flour Beetle vs. Look-Alikes: No Snout, Visible Head
| Beetle | How it differs | How to tell |
|---|---|---|
| Red flour beetle | Flat, shiny, in flour | Antenna club widens suddenly |
| Confused flour beetle | Almost identical | Antennae widen gradually |
| Drugstore beetle | Smaller, oval | Head tucked under; grooved wing covers |
| Rice weevil | Similar size | Long snout; lives inside whole grains |
A beetle with a long snout in rice, beans or whole grain is a weevil, not a flour beetle; see how to get rid of weevils.
Where You’ll Find Them: Milled and Broken Products
- Flour, cake and pancake mixes, cornmeal
- Cereal, crackers, pasta, dried pet food
- Cracks in shelves where spilled flour collects
In warm temperatures, pantry beetles like these can go from egg to adult in about 45 days (UC IPM).
Are Flour Beetles Harmful? They Ruin Flour
They don’t bite or spread disease. Large numbers make flour look grayish and give it a sharp, unpleasant smell.
How to Confirm It’s Flour Beetles
- Sift a little flour onto white paper and look for small reddish beetles or pale larvae.
- Check shelf cracks where flour has spilled.
- Look for gray, sharp-smelling flour in older bags.
What to Do: Toss, Vacuum, Seal
Throw out infested products, vacuum shelves and cracks, and buy smaller amounts if flour sits for months. The steps are the same cleanout used for pantry moths: find every infested package, throw it out, vacuum the shelves and store dry food in containers with tight lids. UC IPM says plastic bags aren’t adequate, and keeping rarely used flour, spices and grains in the freezer prevents infestations. For other pests, browse all pest guides.
Often confused with
Sources
Last reviewed Oct 4, 2026.
