Clothes moth larvae are small, worm-like caterpillars that feed on animal-based fabrics like wool, silk, fur, and leather. They’re the ones doing the damage to your clothes, not the adult moths you might spot fluttering around. Adult clothes moths don’t eat at all. If you’ve found irregular holes in a sweater or bare patches on a wool rug, larvae are almost certainly responsible.
What They Look Like
Clothes moth larvae are creamy white caterpillars, roughly the size of a grain of rice when young and up to about half an inch long when fully grown. They have a darker head capsule, usually brown or tan. Their bodies are soft and slightly translucent, so you can sometimes see the color of the fabric they’ve been eating through their skin.
Two species cause nearly all clothing damage in homes. Webbing clothes moth larvae leave behind silky tubes and patches of webbing on the fabric surface as they feed. They move freely across the material, trailing silk behind them. Casemaking clothes moth larvae build a small portable case around themselves from fiber fragments and silk. They drag this tiny tube along as they eat, so you might spot what looks like a small grain of fabric debris that actually contains a larva inside.
What They Eat and Why
These larvae feed exclusively on animal fibers: wool, fur, silk, feathers, felt, and leather. What makes them unusual in the insect world is their ability to digest keratin, the tough protein that gives these materials their structure. Most insects can’t break keratin down, which is why clothes moth larvae have such a specific niche.
In the wild, clothes moth larvae feed on bird nests, animal carcasses, and shed fur or feathers. Inside your home, they target the same protein in your wardrobe. They’re especially drawn to items that carry body oils, sweat, or food stains, because these residues provide extra nutrients the larvae need. A clean wool sweater stored properly is far less attractive to them than one worn once and tossed in the back of a closet.
Synthetic fabrics like polyester and nylon are safe from clothes moths. Cotton and linen are also not at risk, since these are plant-based fibers without keratin. Blended fabrics (say, a wool-polyester mix) can still be damaged, though. The larvae will eat the animal fibers and leave the synthetic threads behind, creating a patchy, thinned-out texture.
Life Cycle and Development
A female clothes moth lays eggs directly on or near a food source, typically tucking them into fabric folds or seams. The eggs are tiny, nearly invisible to the naked eye, and hatch in 4 to 21 days depending on temperature.
Once hatched, larvae go through 4 to 6 growth stages before pupating. This feeding period varies dramatically between species and conditions. Webbing clothes moth larvae feed for as little as 35 days or as long as two and a half years. Casemaking clothes moth larvae have a narrower range, feeding for roughly 68 to 87 days. Food availability, temperature, and humidity all influence how quickly they develop. Warmer, more humid environments speed things up. In cooler conditions, larvae can survive for over a year, slowly feeding the entire time.
The pupal stage, when the larva transforms into an adult moth, takes 8 to 40 days. Pupation is slower in winter. Total development from egg to adult generally takes 1 to 3 months under favorable conditions, but can stretch well beyond a year in less ideal environments. This extended timeline is part of what makes infestations so persistent. Larvae can quietly feed in undisturbed areas of your home for months before you notice any damage.
Signs of an Infestation
Because larvae avoid light and prefer undisturbed areas, you’ll usually notice the damage before you see the insects themselves. Common signs include:
- Irregular holes in fabric: Unlike snags or tears, moth damage creates uneven, roughly circular holes, often in clusters.
- Webbing on fabric surfaces: Silky threads or matted patches, especially in folds or seams, are a hallmark of webbing clothes moth larvae.
- Small portable cases: Tiny cylindrical tubes made of fiber fragments on or near damaged items indicate casemaking clothes moth larvae.
- Sandy-colored pellets: Larval droppings (frass) look like fine grains of sand, often matching the color of the fabric being consumed.
- Bare patches on rugs or furs: On textured items, larvae eat fibers down to the backing, leaving thinned or bald spots.
Check the backs of rugs, the insides of closets, under furniture, and along baseboards. Larvae gravitate toward dark, still, warm spaces. Items stored for long periods without being moved are at highest risk.
Are They Harmful to People?
Clothes moth larvae don’t bite or sting. They have no interest in human skin and pose no direct physical threat. However, some people experience allergic skin reactions from contact with moth larvae or the tiny hairs and fragments they shed. These reactions can include itching or mild rashes that might be mistaken for insect bites. If you’re handling infested items, washing your hands and the clothing afterward is enough to avoid irritation for most people.
How to Kill Clothes Moth Larvae
Freezing is one of the most effective and fabric-safe methods. Place the infested item in a sealed plastic bag and put it in a freezer set below 18°F for several days. This kills larvae and eggs without exposing your clothes to chemicals or water. It works well for delicate items like cashmere, silk scarves, or heirloom textiles that can’t be machine washed.
Heat also works. If the fabric can handle it, running items through a hot dryer cycle will kill all life stages. Washing in hot water before drying adds extra insurance. For items too large or delicate for the dryer, dry cleaning is effective because the solvents kill larvae on contact.
Vacuuming is critical for carpets, rugs, and closet floors. Focus on edges, corners, and under furniture where larvae tend to congregate. Dispose of the vacuum bag or empty the canister outside immediately afterward.
Prevention That Actually Works
The single most effective prevention step is regular cleaning. Larvae target soiled garments, so washing or dry cleaning wool, silk, and other vulnerable fabrics before storing them removes the body oils and food residues that attract egg-laying moths. Clean clothes stored in sealed containers or garment bags are rarely damaged.
Mothballs do work, but come with significant drawbacks. They contain either naphthalene or paradichlorobenzene, both of which release toxic fumes. They’re only effective in enclosed spaces where the gas can build to lethal concentrations, so scattering a few in an open closet does essentially nothing. If you use them, they need to be inside a sealed container with the clothing, and the fumes need to dissipate before you wear the items.
Cedar products, while popular, have limited effectiveness. Fresh cedar oil can repel adult moths from laying eggs, but the concentration fades quickly and it doesn’t kill larvae already present. Pheromone traps (the sticky traps sold for clothes moths) attract adult males, which helps you monitor whether moths are active in your home. They won’t stop an existing infestation, though, because they don’t target the larvae doing the actual damage.
For long-term storage, airtight containers or vacuum-sealed bags are your best protection. Clean the items first, seal them completely, and larvae simply can’t access the fabric. This approach is more reliable than any repellent, and it works indefinitely.