Fabric Insect Pests:  Moths & Carpet Beetles
Sharon Stevens, Former Assistant Coordinator, Missouri Textile and Apparel Center,
College of Human Environmental Sciences, University of Missouri-Columbia

Clothes moths are usually blamed for insect damage on fabrics, but other insect pests, most notably carpet beetles, are also able to cause serious damage.

The immature stages (larvae) of both the clothes moth and carpet beetle feed on a variety of animal-based material, including wool, fur, silk, feathers and leather. Items commonly infested include wool sweaters, coats, clothing, blankets, carpets, down pillows, and comforters, natural bristle brushes, toys and animal trophies.

Neither the clothes moth nor the carpet beetle can digest cellulosic fibers such as cotton, linen, or rayon, or synthetic fibers such as polyester, nylon, or acrylic, so these are usually safe. However, synthetic fabrics that are blended with wool may be eaten. Cotton, linen and synthetics heavily soiled with food stains or body oils may also be occasionally attacked.

How to Identify the Clothes Moth:

Clothes moths are small (about ½ inch), buff-colored moths with narrow wings fringed with hairs. Adult clothes moths are seldom seen because they avoid light. Adult clothes moths do not feed so they cause no injury to fabrics. However, the adults produce eggs, which hatch into fabric-eating larvae. In the larval stage, clothes moths are creamy-white caterpillars up to ½ inch long.

Webbing clothes moth larvae spin silken feeding tunnels or patches of webbing as they move about on the surface of fabrics. They often deposit tiny fecal pellets similar in color to the fabric.

Casemaking clothes moth larvae enclose themselves in a portable case that they drag with them wherever they go. Often they leave the material they developed on and can be seen crawling slowly over walls or ceilings. This moth may travel a considerable distance to spin a cocoon in a protected crack or along the juncture of a wall and ceiling.

How to Identify Carpet Beetles:

There are many different species of carpet beetles. The adults are small, oval-shaped beetles about 1/8 inch long. The most common, the black carpet beetle is shiny black; others are brightly colored in various patterns of white, brown, yellow and orange.

The larvae are about 1/8 inch to ¼ inch long and densely covered with hairs or bristles. Only the larval stage feeds on fabric and causes damage. They will also feed on seeds, pet food, or cereal products. In nature the adults feed on flowers outdoors. If they are seen indoors, around light fixtures and windows, there is a larval infestation present somewhere within the home.

Habits of Both Pests:

The larvae of both prefer to feed in dark, undisturbed areas such as closets, attics, and within boxes where woolens and furs are stored for long periods. Clothing and blankets in constant use are seldom damaged by these pests nor are carpets that get normal traffic or are routinely vacuumed. The edges of carpets next to walls or underneath furniture are often attacked.

These pests may also be found in upholstered furniture (both inside and out) and in air ducts where the larvae may be feeding on lint, shed pet hair and other debris. Infestations may also originate from bird or animal nests, or an animal carcass present in an attic, chimney or wall space. Adult carpet beetles may fly from one house to another or eggs or larvae may be transported into a home on articles containing wool or other animal fibers.

Damage to articles may consist of irregular surface feeding or holes eaten completely through the fabric.

Prevention:

Good cleaning is the best prevention. Vacuum carpets thoroughly and frequently. Pay close attention to dark, out-of-the-way places. If you have pets, clean more often since pet hair is a good source for these pests.

Elimination:

If insect damage is suspected check all susceptible items carefully. Look in back corners of the closet, hat boxes, remnants of wool fabric or carpeting. Clothes moths and carpet beetles often breed in hair-based accumulations that might be found behind baseboards, under door jambs, inside heating vents, etc. Clean and vacuum carefully.

When infested areas are cleaned well, it may not be necessary to apply an insecticide. If an insecticide is used, treat only cracks, crevices, and invested areas. Sprays may be applied to infested carpets (especially along and beneath edges adjacent to baseboards) and underneath furniture. NEVER spray clothing or bedding directly. These items should be removed before spraying inside closets or drawers. Always read the label on household sprays and follow product directions carefully.

Before returning items to storage areas, either launder or dry clean them, use another method of control, or get rid of them.

A widespread infestation may require the services of a professional pest control operator who can better access difficult places such as walls and attics.

Laundering/Drycleaning:

Both laundering in hot water and drycleaning will kill all stages of fabric pests and will also remove perspiration odors that are attractive to pets. Woolens and other susceptible fabrics should be drycleaned or laundered before being stored for long periods. NOTE: Most animal-based fibers cannot tolerate hot water without shrinking or other damage. Read and follow the care label before attempting to wash these fabrics.

Storage/Fumigation:

The vapors from moth balls, crystals or flakes containing paradichlorobensene (PDB) or naphthalene, are lethal to fabric pests, but only when maintained at sufficient concentrations. To ensure this, enclose the manufacturer's recommended dosage in containers that are practically airtight. Trunks, garment bags, boxes and chests, when tightly sealed, will be effective. Do not use PDB in plastic containers.

Contrary to popular belief, cedar chests and closets are seldom effective in preventing fabric pest infestations because the seal does not keep in enough concentration of the volatile oil of cedar.

Do not place any insecticide directly on fabric. Either place mothballs, flakes, or crystals on a layer of paper on top of items in a box or chest or layer the clothing and place paper and moth control product between the layers. If using a garment bag, suspend the moth control product in an old sock or nylon stocking at the top of the bag or use a moth cake. Clothing should be loosely separated.

The length of exposure needed to kill clothes moths or carpet beetles will vary with the temperature, the size of the larvae, and the form, concentration and which variety of insecticide is used. Several days is usually sufficient to kill most infestations, but older larvae and most stages of carpet beetles may require two to three weeks.

Brushing:

Clothing may be thoroughly brushed at regular interval (once or twice a month) to control moths. Brushing should be done outside. All areas should be brushed including pocket flaps and under collars.

Cold Storage: Although cold storage temperatures (at 40 degrees F) may prevent larvae from feeding it does not kill them. Furs should be cleaned prior to cold storage by a professional cleaner using the furrier method.

Mothproofing:

Mothproofing is a chemical treatment given to fabrics that protects them from insects without leaving any odor. A label stating "mothproof" or "moth resistant" means that the item has been treated during manufacturing. This process is considered permanent.

Information adapted from University of Kentucky Cooperative Extension Service, Bulletin IP-50, by Betty Jo Dedic and Mike Potter, 1996

See related articles elsewhere on this website for information on removing persistent odors.

No endorsement of companies or their products mentioned is intended, nor is criticism implied of similar companies or their products not mentioned.