Clothes moths are typically cited as the culprit for infestation and damage of fabrics. However, other pests, including carpet beetles, are also capable of damaging textiles such as carpets, rugs, clothing, and furniture. Infestations may go undetected for long periods of time, allowing for extensive damage if left untreated. This publication discusses how to recognize clothes moths and carpet beetles, as well as how to manage and eliminate an infestation.
Clothes moth larvae (the juvenile or immature life stage) is technically a type of caterpillar. They feed mostly on wool, fur, hair, horns, hooves, feathers, and occasionally on organic materials like leather, lint, mohair, and silk. Larvae of this pest are after keratin, a protein found only in animal-based materials. They are one of the few insect pests that can successfully digest this complex protein. Fabrics stained with food, perspiration, and oils are especially vulnerable. Most damage to these materials is done when the larvae are undisturbed for long periods of time, such as in forgotten bins of stored clothing or carpet under heavy furniture. Larvae cannot digest fibers made from cellulose, such as cotton, rayon, or linen, so purely synthetic carpets and other materials are not eaten. However, synthetic fibers blended with animal components such as wool may be incidentally attacked, as can synthetic fibers stained with food and other oils.
Larval clothes moths are small, creamy-white caterpillars approximately ½ inch in length. Adult clothes moths are small, buff-colored insects about ¼ to ½ inch in length. Adults have four wings, are weak flyers, and, since they avoid lighted areas, are seldom seen. They prefer to rest in dark, undisturbed areas such as closets, attics, or basements, and will also live in the folds or seams of fabrics. Any small moths seen flying around the room and toward lights are probably not clothes moths. Instead, small moths flying in open areas such as a kitchen could be grain moths, which attack stored food products. When an adult female clothes moth finds a suitable area (where larvae will have plenty of food to eat upon hatching), she can lay between 100 and 300 eggs. Only the larval life stage feeds on textile items; adult clothes moths do not eat and cause no direct damage. After feeding on clothing and other textiles, larvae enter the pupal life stage by spinning cocoons. New moths will emerge from these cocoons 8 to 10 days later. It can take three months to multiple years for larvae to enter the pupal life stage.
The most prevalent clothes moth species in North Carolina is the casemaking clothes moth (Tinea pellionella) (Figure 1 and Figure 2). When a juvenile clothes moth is ready to pupate, the larva crawls up and attaches itself to a wall, ceiling, or other high place. There it spins a case from silk combined with pieces of debris and fabric on which it has been feeding. The appearance of these cases (which may be attached firmly to a substrate or hang downward) and small caterpillars climbing up the walls can alert the homeowner that they have a clothes moth problem (Figure 3 and Figure 4). The color of the case depends on the color of the fabric on which the larva has been feeding. Matching the colors in the case with susceptible fabrics stored nearby may lead the homeowner to the source of the larval infestation.
Another type of clothes moth, the webbing clothes moth (Tineola bisselliella), does not make cases. They are usually found under silken webbing spread over the infested fabric. This moth is seldom found in North Carolina.
Carpet beetles and clothes moths overlap in many of their habits and feeding preferences. Like juvenile clothes moths, carpet beetle larvae also feed on animal materials such as wool, fur, hair, feathers, glue, book bindings, silk, horns, bone, leather, and dead insects. They attack cotton, linen, and synthetic fibers only if the items are soiled. Some carpet beetle species can infest cereals, cake mixes, spices, flour, powdered milk, and pet foods, but these are most often not the same species that attack fabrics. Adult beetles and larvae live around baseboards and moldings, in heating and cooling system ducts and vents, dresser drawers, carpets, clothing, and upholstered furniture. Adult beetles mainly feed on flower pollen and nectar outdoors. Adults do not feed on fabric and are often found at windows and on windowsills during the spring (Figure 5).
Adult carpet beetles are small, about 1/16 to 3/16 inches long. They may be black, or mottled with white, gray, orange, yellow, and red (Figure 6). Adult female beetles lay about 100 eggs in areas where the larvae will have a food source available upon emergence. After eggs are laid, larvae will emerge in one to two weeks. Larvae resemble tiny, hairy caterpillars or bottle brushes, and the most common species have large tufts of hairs on the back end (Figure 7). They feed for nine months to three years before pupating and transforming into adult beetles.
Habits of Clothes Moths and Carpet Beetles
As described, the larvae of clothes moths and carpet beetles attack clothing and a wide range of household furnishings, including blankets, down comforters, pillows, rugs, carpets, draperies, natural bristle brushes, upholstery, taxidermy, and decorative items. Only animal-based materials that contain organic compounds and the protein keratin are damaged. For the most part, synthetic and plant-based fibers like cotton and linen are undesirable, especially if they are clean when stored, but wool blends may be attacked. As the larvae feed on and digest the wool, they can also damage other fibers. Textiles soiled with food, body oils, feces, and urine are most susceptible. Carpet beetle larvae tend to chew holes through fabric. Clothes moth larvae prefer to graze along the surface, but they can make holes too.
Larvae prefer dark, undisturbed areas and they can attack a wide array of items — making detection difficult in many cases. They may even attack mounted animal trophies, felts in seldom-used pianos, or stored locks of baby’s hair. Do not overlook seemingly unlikely or forgotten decorative items when inspecting (Figure 8).
Some infestations occur when adult carpet beetles or clothes moths fly from one house to a nearby house. Occasionally carpet beetles breed and feed outdoors in places such as bird and rodent nests (or abandoned wasp nests) and may enter homes from these locations or from garden bouquets brought indoors. Eggs or larvae may hitchhike into a home on articles containing wool or other animal fibers, particularly secondhand clothing, upholstered furniture, and woolen scraps exchanged for making rugs or quilts.
Once the insects gain entry, the larvae may crawl from room to room, closet to closet, or rug to rug, slowly causing damage to the fabric. It usually takes at least a year to reach major infestations, particularly if the homeowner does not watch for signs of a pest problem. These insects work and reproduce slowly, so the earlier you discover an infestation and the more quickly you react, the more likely you are to prevent serious fabric damage. However, it should be noted that all homes surveyed in a recent study contained one or more carpet beetles (Bertone et al. 2016), so finding a few individuals here or there in homes is common. Carpet beetle presence may not necessarily mean that there is a damaging infestation (for example, they are often found feeding on dead insects rather than fabrics).
Good housekeeping is the foundation of any good fabric pest prevention program. Thorough, frequent cleaning and taking special care with those hard-to-reach areas are important, as larvae are so small that they can crawl into nearly any crack or crevice. Deep, attentive cleaning removes debris embedded in rugs and carpets and makes it more likely that you will remove larvae from hidden areas. Pay attention to areas along the walls and under rug edges, couches, sofas, chairs, and chests. Vacuum both sides of area rugs once a month during the summer and every other month in other seasons. Rotate rugs or rearrange furniture periodically to expose different areas of the floor coverings. If you have pets, it may be necessary to take these steps more frequently, as pet hair is a common source of food.
Proper maintenance of fabrics is crucial to preventing infestation. Brush susceptible clothing once a month or every two months, preferably outdoors. Clean woolens (dry clean when possible) and similar materials at the end of the winter and place them into sealed storage containers or bags. Store furs commercially. In addition to protection from insects, furs need controlled temperature and humidity to preserve their integrity. These materials are often stored in cool environments, around 40℉. Coats, suits, and similar items may be stored in tight garment bags with repellents (for example, naphthalene) suspended near the top in a small bag of netting. Repellents may also come in small blocks or pouches that have built-in hooks. Items labeled “moth resistant” or “mothproofed” when purchased were treated with a protective chemical when they were manufactured. Many woolens made in the United States have this protection, which remains effective through many washings and dry cleanings. In addition, some dry cleaning and rug and carpet cleaning businesses offer preventative pest control treatment for fabrics. Some companies can treat cleaned fabric with a chemical that protects the fabric from pests for about six months. However, many dry cleaners no longer offer this service because they lack a practical way to safely dispose of their waste materials.
Pesticides cannot take the place of cleanliness and good storage practices. Few household insecticides can be sprayed on fabrics, and those that are labeled for such use are not likely to provide more than six months of protection against fabric pests. If insecticides are deemed necessary to preventatively treat carpet or other vulnerable items, the best choices for homeowners include pyrethroids, such as tetramethrin, sumithrin, or permethrin. However, before purchasing or using such a product, be sure it is labeled for use in or on sites where clothes moths or carpet beetles frequent.
Mechanical removal of pests is a good first step in eliminating an infestation. First, inspect your home and locate all sources of emerging adult insects. Again, be thorough; these pests attack items that you might not think of as potential food sources. All infested articles should be cleaned according to manufacturer directions or discarded if they cannot be salvaged. Be careful not to spread the infestation by moving infested items throughout the home during cleaning and treatment. Thoroughly brush or vacuum items, giving special attention to seams, pockets, and cuffs. It is ideal if this step is done outdoors. Then, dry clean or launder using hot water, if it will not damage the fabric. Laundering and dry cleaning will kill all life stages of insects in fabrics, but it will not protect against future infestations.
If infested areas are cleaned thoroughly, it may not be necessary to apply pesticides in a remedial fashion. If a liquid pesticide is used, treat only cracks, crevices, and hidden surfaces with a residual spray designed for use by homeowners on carpet beetles or clothes moths. It is not necessary to treat walls, ceilings, or storage shelf surfaces. Many of the household pesticides labeled for ant and cockroach control are also labeled for fabric pests. However, most of these insecticides may be used only on storage surfaces; only a few may be used directly on fabrics. Before using an insecticide for any purpose, read the label thoroughly and follow the directions carefully.
Multiple fabric pest products are available for both repelling and treating these pests; the most recognizable of these contain paradichlorobenzene (PDB) or naphthalene. These are the active ingredients in many products such as mothballs, crystals, and flakes. You can use these products to treat infested articles as well as repel newly invading fabric pests. The vapors from these active ingredients are lethal to all stages of fabric pests, but they must reach a specific concentration for optimal efficacy, especially if they are being used to kill older stage clothes moth larvae or carpet beetles. To achieve sufficient lethal concentrations of product, place the recommended dosage (use the product label for reference) of these insecticides in tightly sealed containers. You can seal boxes or other containers with tape to prevent leakage of air. Since the vapors of many of these products are heavier than air, the insecticide should be placed higher than the items to be treated so that vapors can sink. Do not place chemicals directly on fabric as they may affect the dye. If the container you are using for treatment is deep, layer the fabrics and place the product between each layer. Do not use PDB in plastic containers or bags because it can melt or damage certain types of plastic, ruining the clothing inside. Polyethylene garment bags are a great choice for housing clothes during treatment because they are not affected by PDB vapors. However, if you must use plastic bags or containers for treatment, use naphthalene instead of PDB. In general, it is not a good idea to use plastic bags for textile storage, as they limit air circulation and can promote the growth of mold on fibers. Finally, fabric pest control products MUST be used according to label instructions. When misused, they can be toxic to people and pets. If you can smell the mothballs, you are being exposed to the active ingredient and have not achieved a tight seal in your container. After treatment, air the items out in an open space.
Dichlorvos (DDVP) strips are also acceptable for use against flying and crawling pests, including moths and beetles. However, it is extremely important to follow label directions to achieve optimal efficacy as well as to avoid human and animal pesticide exposure. Products containing DDVP are meant to be used in enclosed spaces that are mostly uninhabited by humans. Dichlorvos strips would be an acceptable product choice for an attic, but an inappropriate choice for a closet used daily, for example.
While homeowners may control many infestations, professionals are able to treat hidden infestations in closets or rugs and carpets most effectively. Treating valuable items, such as expensive rugs, furs, carpets, and pianos, definitely requires the help of professionals. The homeowner who tries to treat such infestations may fail to eliminate the problem and damage the item in the process. Also, pest control operators may use certain insecticides not available to the public.
Once the infestation is eliminated, follow the preventative advice given in this publication to prevent a new infestation.
Stategies with Limited to No Efficacy
Cedar wood storage chests and closets do not keep woolens and furs safe from clothes moths and carpet beetles for long periods. The mothproofing value of cedar wood disappears after about two years. However, most cedar closets and chests are carefully constructed and make excellent storage containers, particularly when an insect repellent is used in them. Frequent use will allow vapors to escape, reducing the longevity of repellent compounds.
Sunning items exposes the insects to heat, light, and activity and upsets their lodging but may not be enough to get rid of an infestation. Combine sunning with vigorous brushing of the articles to dislodge insect eggs and larvae.
Herbs and spices placed in storage containers may provide some very limited repelling effects, but they do not protect susceptible articles from fabric pests. Some of these plant products, if hung in closets, may actually attract pantry pests such as cigarette and drugstore beetles.
Bertone, M., M. Leong, K. Bayless, T. Malow, R. Dunn, and M. Trautwein. 2016. “Arthropods of the great indoors: Characterizing diversity inside urban and suburban homes.” PeerJ (January).
This publication is an updated version of an earlier publication. The authors would like to thank the original authors for their contributions: Michael Waldvogel, Extension entomologist, Judieth Mock, Extension human environment specialist, and R.C. Hillman, Extension entomologist emeritus.
Publication date: June 14, 2021
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