Besides pantry moths, the bugs you’ll find in dry food are mostly small beetles: cigarette and drugstore beetles, flour beetles, sawtoothed grain beetles, warehouse beetles and weevils. Many are tiny and reddish-brown, but size and shape differ per species (see the list below). They usually arrive in an infested package. The fix is the same as for moths: throw out infested food in a sealed bag, check everything else, vacuum and wash the shelves, and store dry food in tight glass, metal or heavy plastic containers.
Moth or Beetle?
If something flies out when you open the cupboard, it’s probably a moth (see pantry moths). If you find small brown bugs crawling in the flour or the rice, they’re more likely beetles. UC IPM says the most common food-infesting insects belong to two groups: moths and beetles. For the larvae, UC IPM gives a handy difference: moth larvae have three pairs of legs near the head plus leg-like parts farther back, while beetle larvae are grub-like with no legs or just three pairs near the head.
The Usual Suspects
Cigarette and drugstore beetles
About 1/8 inch, reddish-brown and oval. The head is tucked under, so you can’t see it from above (Illinois).
Flour beetles
Similar size and color, but the head is visible from above (Illinois). Red and confused flour beetles develop in about six weeks in summer (UC IPM).
Sawtoothed grain beetle
A common grain pest; development takes three to four weeks in summer (UC IPM).
Warehouse beetle
Oval, about 1/8 inch. The larvae have stiff hairs that “can irritate your mouth, throat, and digestive tract” (UC IPM).
Weevils
UC IPM names bean, granary and rice weevils as seed beetles in stored food, without covering them in detail.
Illinois says beetle larvae are often hairy and cream-colored. Beetles infest a wide range of foods: UC IPM lists pet food, spices, cereals, nuts and dried herbs, and Illinois adds rice, flour, pasta, cornmeal, oatmeal, dried fruit and birdseed.
How They Get Into Your Pantry
Like pantry moths, beetles “usually enter your home in an infested package of food,” according to UC IPM. Packages damaged at the store and opened packages that sit around for months are the usual start. Illinois warns that pests can chew through paper, cardboard and thin plastic, so one infested box can spread to the bag of rice next to it.
How to Get Rid of Pantry Beetles
- Find the infested food. Look in flour, rice, pasta, cereal, spices, nuts, dried fruit, pet food and birdseed.
- Seal it in a bag and take it outside (UC IPM, Illinois).
- Check everything else, especially opened packages. UC IPM says to destroy any package with “the slightest indication of infestation.”
- Vacuum corners and cracks with a crevice tool and empty the vacuum afterwards (Illinois).
- Wash shelves with soap and water (UC IPM), and clean old containers before you refill them (UC IPM).
- Freeze what you want to protect. Illinois gives 27°F or colder for 3 to 7 days; Utah State gives 0°F or lower for 4 to 7 days. Neither source explains why its numbers differ, but a home freezer should already be at 0°F (FDA), which meets both. My default: a full week in a normal freezer, a bit longer for big or thick packages so they freeze all the way through.
- Monitor. UC IPM says beetle traps use aggregation pheromones that attract both males and females. A new catch means checking your packages again.
Keep Them Out
- Store dry food in tightly closed glass, metal or heavy plastic containers (Illinois); plastic bags are not adequate (UC IPM).
- Keep rarely used flours, grains and spices in the freezer (UC IPM).
- Don’t mix old and new food in one container, and clean containers before refilling (UC IPM).
- Buy only what you’ll use soon and use older products first (Illinois).
Storage tips: how to keep flour fresh, how to store rice, rice long term, nuts, and the pantry storage collection.
Clean Out Safely
- No sprays or bug bombs in the pantry. UC IPM: insecticides “aren’t recommended for any of the pantry pests.” Illinois: food that touches an insecticide must be thrown away.
- Throw out infested food. UC IPM warns about mycotoxins from microbes the pests bring in, and about the irritating hairs of warehouse beetle larvae. More in is infested food harmful?
- Never heat flour in the oven to kill bugs: Utah State warns of fire or explosion.
Pantry Bug Questions
What are the little brown bugs in my flour?
Usually small pantry beetles. Cigarette and drugstore beetles, for example, are about 1/8 inch, reddish-brown and oval with the head tucked under; flour beetles look similar but show their head from above (Illinois). Throw out the infested flour in a sealed bag and check the rest of the pantry.
How did bugs get into my rice?
Most often they came home in an infested package, according to UC IPM. They can also move from one package to another, because pests chew through paper, cardboard and thin plastic.
Can I freeze flour to kill bugs?
Yes, for flour you want to protect or that is only lightly infested. Illinois gives 27°F or colder for 3 to 7 days and Utah State 0°F for 4 to 7 days; my default is a full week in a normal 0°F freezer. Don’t heat flour in the oven: Utah State warns of fire or explosion.
Do bay leaves keep bugs out of flour?
The extension sources I used don’t recommend bay leaves. They recommend tight glass, metal or heavy plastic containers, the freezer for rarely used flour, and buying smaller amounts.
Sources & Transparency
Moths and beetles, larvae legs, beetle species and timing, warehouse beetle hairs, weevils, entry in packages, clean-out, aggregation pheromone traps, containers and insecticides: UC IPM Pest Notes: Pantry Pests (Publication 7452). Beetle identification, larvae, foods, chewing through packaging, freezing and insecticides: University of Illinois Extension, “Pantry Pests”. Freezing at 0°F and the flour warning: Utah State University Extension, “Winter Pests in Your Pantry”. Freezer temperature: FDA, “Are You Storing Food Safely?”. Tips marked as mine are my own advice.
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