Signs of Infestation of Moths & Beetles

Cloth Damage

• Both clothes moths and carpet beetles leave holes in household fabric items. The larvae of these insects actually feed on cloth, posing a threat to anything made of wool, fur, hair or feathers, such as clothing, carpets, blankets or cloth furniture. Additionally, clothes moths typically hide in dark places, presenting more threat to clothing or fabric kept in dark closets. In both species, adults do not feed on cloth.

Bugs in Food

• The most telling sign of infestation is when insect larvae, dead or alive, appear inside a container of food. Most moths and beetles are attracted to grain-based foods. In particular, the Indian meal moth likes dried pet food and birdseed. Dermestid beetles prefer animal matter, like meat, while spider beetles prefer moist, moldy grain-based products. Some species eat whole grain foods, but others, like the sawtoothed grain beetle and most species of flour beetles, only infest processed grain products like flour.

Chewed Cardboard

• If you keep your dried foods in their original packaging, you may face greater risk of an insect infestation. Most pantry pests can chew through cardboard, paper and plastic wrappings. Under most circumstances, keeping dried foods in screw-top glass, metal and heavy plastic containers prevents most pantry pest infestations, but some species, like the drugstore beetle, can even chew through tinfoil and sheet lead.

Food Damage

• Moths and beetles that act as pantry pests leave behind microbes and other irritants. Indian meal moth larvae leave behind frass, or excrement, and several beetle species leave secretions that affect the taste and odor of food. Warehouse beetles also leave setae, or hairs, that irritate the mouth and throat when consumed. Moreover, some of the microbes left behind can produce mycotoxins, a cancer-causing compound.

Cast Skins

• While you may not see any actual larval or adult insects, some species leave behind other physical evidence of their presence. Dermestid beetles, including the carpet beetle, often shed their larval skins in dark, undisturbed places, including inside air ducts, beneath furniture, under baseboards and in dark cupboards near dried cereals.

Webbing

• Webbing is another type of physical evidence left behind by several insects. In particular, the larvae of the Indian meal moth leaves a silk webbing behind once it establishes a food source, often in dark cupboards containing pet food, seed or dry grain-based products. The larvae of webbing clothes moths also leave behind a silken webbing near their food source: cloth-based items.