The short answer
Clothes moth larvae are small, shiny, creamy white caterpillars with a brown or dark head, growing to about 11 mm. They live in dark, undisturbed places on wool, silk, fur and feathers, under silk webbing or inside a small case, and they do all the damage. Adult moths never eat fabric.
Most people only notice moths when they see the adults flitting out of a wardrobe. But the adults are not the problem. The damage to your clothes, rugs and carpets is done entirely by the larvae, and they are much harder to spot.
What clothes moth larvae look like
Two moths do almost all the textile damage in British homes: the webbing clothes moth and the case-bearing clothes moth. Their larvae look very alike.
- Colour: shiny, creamy white, sometimes slightly see-through, so you may see a dark line where they have been eating.
- Head: a small, hard, brown to black head capsule.
- Size: tiny when they hatch, growing to about 11 mm, roughly the length of a grain of long rice, according to the MuseumPests fact sheet.
- Shape: a smooth, slightly tapered caterpillar with no hairs to speak of.
The webbing clothes moth larva spins patches of silk webbing and tunnels as it feeds, and often leaves silky tubes woven into the fabric.
The case-bearing clothes moth larva carries a portable silk tube around with it, open at both ends, which takes on the colour of whatever fibre it has been eating. UC IPM describes mature cases as cigar-shaped and about 10 mm long. If you find what looks like a tiny grey or beige grain of rice that moves, it is probably one of these.
How they differ from carpet beetle larvae
This matters, because the treatment and the places to search differ.
| Clothes moth larvae | Carpet beetle larvae | |
|---|---|---|
| Body | Smooth, creamy white | Bristly, banded brown |
| Head | Dark, distinct | Hidden among hairs |
| Silk | Webbing or a case | None |
| Holes | Irregular, grazed areas | Small, clean, round |
| Left behind | Gritty droppings, webbing | Papery cast skins |
If you are finding hairy brown grubs, see our guide to carpet beetle larvae.
What moth larvae eat
The larvae digest keratin, the protein in animal fibres. MuseumPests lists wool, mohair, feathers, fur, hair, felt and the dust that contains them as food, along with carpets, rugs, blankets, upholstery and piano felts. Cotton and synthetics are not food, but can be damaged if they are mixed with wool or soiled.
Stains make a difference. Sweat, body oils and spilt food make a garment more attractive, which is why moths go for the jumper you wore once and put away without washing, and why damage often starts under the arms, on collars and cuffs.
Where they hide
Larvae avoid light. UC IPM notes that they will drop from clothing rather than stay exposed. Look in places that stay dark and undisturbed:
- under collars and cuffs, in seams and behind labels
- in the folds of stored knitwear and blankets
- along the edges of wool carpet and under the gripper rods
- under beds, sofas, chests and wardrobes that are never moved
- inside ottomans, blanket boxes and under-stair cupboards
- in the deep folds and buttons of upholstered chairs
English Heritage also suggests checking lofts and attics for old bird nests, which can feed a population that then spreads.
How long the larval stage lasts
From 35 days to two years, depending on the temperature and how good the food is, according to MuseumPests. In a warm, centrally heated London flat they develop quickly and can breed all year. In a cold spare room they may sit in a box of jumpers for a long time before anyone notices.
What the signs of larvae are
If you cannot find a larva, look for what they leave behind:
- irregular holes or thin, grazed patches in wool
- silk webbing or small tubes in folds and corners
- droppings, called frass: tiny grains, often the colour of the fabric
- bare patches in carpet, especially along the skirting
- empty cases in the corners of drawers and wardrobes
How to get rid of moth larvae
Clean out the area
Empty the wardrobe or drawer. Vacuum every corner, shelf and seam slowly, and get into the edges of the carpet underneath. Seal the vacuum contents in a bag and put it straight in an outside bin.
Deal with every item
- Wash on a hot cycle anything whose label allows it.
- Dry clean what cannot be washed.
- For delicate wool and silk, English Heritage advises sealing items in freezer bags and freezing them at -18°C for at least two weeks, which kills adults, eggs and larvae.
- Brush and air heavy coats and tweeds, paying attention to seams.
Store things sealed
Put only clean items back, in sealed bags or tightly closed boxes. Larvae cannot eat through a properly sealed bag.
Use traps to monitor, not to cure
Pheromone traps catch males only. They show you whether moths are still breeding, but will not end an infestation by themselves.
When to get help
If larvae keep turning up after you have done all this, or the damage is in fitted carpet, rugs or several rooms, a professional treatment will reach places you cannot. In London, that typically costs £150 to £220 for one wardrobe or room. See clothes moth treatment, carpet moth treatment or the price calculator.
For a professional look at the problem, give us your postcode and we will name a moth specialist near you.