By Bud Coburn
Clothes moths readily damage natural fibers and can create problems for home dwellers, but these insects are among the most misunderstood of household pests.
Facts and Figures
- Moth larvae, or caterpillars, consume and damage fibers. Adult males search for females, who, in turn, look for places to lay eggs, but neither of them eats anything or damages clothing.
- There are two species of clothes moth, known as casemaking and webbing. The casemaking moth larvae carry a camouflaged silken case, into which they may retreat, if threatened.
Lifecycle and Habits
Female clothes moths lay an average of 40 to 50 eggs over a period of two to three weeks, and they die once their egg-laying has been completed. Males outlive females and continue to mate during the remainder of their lives. Eggs are attached to adhesive secretions, from which they hatch after a period of days. The emerging larvae, which appear shiny white with a dark head capsule, remain for approximately 35 days to 30 months before pupating into adult moths. Adults have a wingspan of about ½-inch, and are golden-colored, with reddish golden hairs on top of the head. Larvae and adults prefer dim areas, and if larvae find themselves in a well-lit room, they will try to relocate beneath furniture, carpet edges or moldings at a room’s edges.
Clothes moths should not be confused with food-infesting moths, which pose no threat to fabrics. Food-infesting moths are larger, at approximately ½-inch in length (rather than ¼-inch), and lack the tufts of hair found on the heads of clothes moths. Their behavior is distinct, too; clothes moths typically stay near the source of the infestation, and they flutter about in a seemingly absent-minded manner, making them easier to catch than food-infesting moths, which fly in a more direct, steady path.
Moths are often mistakenly blamed for damaged fabric, so it’s important to clearly evaluate their appetite and limitations. Clothes moths exclusively target animal fibers, such as wool, feathers, fur, hair, silk and cashmere, especially where they are stained with beverages, urine, sweat, or oil from hair. Carpet beetles, too, readily consume animal fibers, which can further hamper the accurate identification of the source of the damage. Cellulose fibers, such as cotton, and synthetic fibers, such as polyester, are usually safe from the ravaging mouths of moth larvae, although these fabrics may be eaten if they are heavily soiled or blended with wool or other animal fibers. The most heavy damage is suffered by articles left undisturbed for a long time, such as old military uniforms, blankets, wool upholstery, feathered hats, antique dolls and toys, natural-bristle brushes, weavings, wall hangings, piano felts, old furs, and stored wool carpets and clothing.
Repellents and Insecticides
- Mothballs are small balls of chemical pesticide and deodorant used for the protection of stored clothing and other articles susceptible to damage from moths and their larvae. Both naphthalene and paradichlorobenzene – the two chemicals used to create moth balls — sublimate, meaning that they transition from a solid straight to a gas. For these chemicals to be effective, the mothballs need to be placed with the clothing in a sealed container so that the fumes can build up and kill the moths. Beware that mothballs are highly toxic when ingested, causing serious illness or death. In addition to this, using a very large quantity of mothballs in a basement or a living space may cause serious respiratory problems in people.
- Cedar blocks, shavings and oil are often used as natural moth repellents. Although it’s likely that cedar can protect clothing from moth larvae attack, its mechanism of action is poorly understood, which often leads to ineffective implementation of the substance. Contrary to popular belief, it’s unlikely that cedar actually harms moths or their larvae, unlike naphthalene or paradichlorobenzene. It might not necessarily repel them, either; cedar, like other repellents, occupies the moth’s sense of smell, disguising the aroma of wool, their natural target.
- Practice good housekeeping. Regularly vacuum rugs, carpets, drapes, upholstered furniture, pet bedding, closets, cracks and crevices in floors, and areas inside and behind heaters, furnace air ducts and vents to prevent the buildup of materials on which moths feed, such as lint, dust and hair. Particularly susceptible are areas that are under furniture that is seldom moved, and along baseboards where wool lint may accumulate. After using the vacuum, empty the bag immediately because it may contain eggs or larvae.
- Clean garments regularly and thoroughly. Clothes moths are attracted to articles soiled by food, beverages, perspiration and urine. Regular washing and dry-cleaning are both effective.
- Store articles properly. Place clean articles in tight storage containers or plastic bags that lack holes or tears. Storage containers should have tight-fitting lids, and they can be sealed even more tightly with tape.
- Place garments in cold storage where temperatures remain below 40° F, as larvae are inactive at this temperature, and adult moths slow down. Freezing temperatures usually fall short of eliminating moth populations, however, as they can survive for long periods in unheated attics and barns in old furniture, clothing and blankets.