By Chris Williams on November 17, 2017.

I just opened a box of cake mix and discovered lots of dark bugs moving around inside. When I looked it up on the Internet, it seems like they are some kind of food beetle but there are so many different types, how do I know which one I’m dealing with? F. A., Brookline, MA

The short answer is that it usually doesn’t matter; control and prevention measures are pretty much the same for all food beetles. The beetles that we commonly find in stored foods include the flour beetles, various grain beetles, cigarette beetle, drugstore beetle, rice weevil, sawtoothed grain beetle, and warehouse beetle, to name a few. As you can guess from the names, some have food preferences but most feed on a wide variety of foods from flour to spices to dried fruit (see Flour Beetles Are Just One Type of Stored Food Pest).


Most of these food beetles are tiny (1/8 inch) and usually dark brown.  They are most common in stored or packaged foods that are damp, old, damaged, or beyond their use-by date. In other words, foods that have been pushed to the back of the shelf and forgotten. Usually both adult beetles and larvae feed in the product but the larval stage does most of the feeding damage and contamination.

Knowing the beetle might matter if you are trying to determine what other foods or items in your home could be infested. In most cases though, you will need to check all of the food packages on your shelves. Although most of these beetles feed on a wide variety of foods, some feed primarily on whole grains such as beans, rice, dried corn, or oats while others such as warehouse or hide beetles are just as likely to infest wool, hides, or a dead mouse in another part of your home.


  • Start with the oldest items on your shelves. Even unopened boxes or bags can be infested. In the case of moths, you may find webbing or cocoons under the flaps of sealed boxes or bags.
  • Empty each box or bag onto a cookie sheet in a well-lighted area. Use a knife or spatula to spread out the product and examine it closely. A flashlight and magnifier may help.
  • Look for tiny adult beetles or moths. It’s harder to see beetle larvae so look for movement. You may see shed skins left behind when larvae molt. In a moth infestation, you may see silk webbing left by larvae in the food product. You may find more than one type of beetle in the food, or it may be infested by both beetles and food moths.
  • If the product appears infested, discard it in a sealed plastic bag. If it is pest-free, repackage it in a pest-proof plastic or glass container with a tight-fitting lid. You can also protect products from infestation by keeping them in the refrigerator.

For more on how to clean up after an infestation and how to prevent food pests in the future, see Preventing Pantry Pests – Advice From the Pros.

If your inspection finds many infested products or if you’ve seen food pests wandering in your kitchen, you may need professional help. Even if you throw out all of your packaged foods, there may still be eggs in crevices on the shelves that could reinfest new foods. Call Colonial Pest for a further inspection and treatment of your kitchen and pantry.



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