Clothes Moth Identification: Webbing vs Case-Bearing

A clothes moth is a small, plain moth, about 1/4 inch long at rest with a wingspan of about 1/2 inch, that you find near wool, fur or carpet rather than circling a lamp (UC IPM). Five checks confirm it:

• Size. Wingspan 12-17 mm for the webbing clothes moth and 9-16 mm for the case-bearing clothes moth (Natural History Museum, London).
• Colour. Webbing: plain golden wings with no pattern and a fringe of hairs on the edges. Case-bearing: silver grey-brown wings with one large and two smaller dark spots (NHM).
• Head. A tuft of reddish hairs on the webbing clothes moth, grey hairs on the case-bearing one. UC IPM suggests catching one and checking the head with a magnifying glass.
• Behaviour. They tend to scramble across fabric rather than fly, prefer low light (NHM) and flutter rather than fly in a straight line (UC IPM).
• Place. Closets, bedrooms, wool rugs and stored woollens. University of Maryland Extension lists clothes moths as a buff-coloured nuisance pest of closets and bedrooms.

The two species do the same damage but leave different clues.

• Webbing clothes moth (Tineola bisselliella): golden adult with reddish head hairs. The larva spins silk tunnels and feeding tubes as it eats (UC IPM, NHM) and reaches about 13 mm.
• Case-bearing clothes moth (Tinea pellionella): browner adult with faint dark spots. The larva lives in a portable, cigar-shaped silk case, about 3/8 inch long when fully grown, open at both ends (UC IPM), and reaches about 12 mm. The case takes on the colour of the fibres it has been eating.

If you find silk webbing on the cloth, think webbing clothes moth; if you find small tubes that move, think case-bearing.

Look for the larvae and what they leave, not for the adults. UC IPM lists these signs:

• Silk webs, or silk tubes in hidden parts of garments such as under collars and cuffs
• Silk mats or patches on the fabric
• Surface grazing of the fibres, holes, or both
• On furs, hairs clipped at the base, so fur falls out and the hide shows

Damage is worst on fabric stained with food, sweat or urine (UC IPM). Moth damage tends to be scattered holes, while carpet beetle damage is usually one larger area, with bristly brown cast skins and no webbing (UC IPM); see carpet beetle identification. Only the larvae eat fabric; adult clothes moths do not feed at all (NHM).

• Indianmeal moth: the most common mix-up. It is about 5/8 inch long and the outer half to two-thirds of each wing is reddish-copper (University of Maryland Extension). It lives in the kitchen or pantry, in flour, cereal and nuts, and flies readily. See household bug identification.
• Brown house moth (Hofmannophila pseudospretella): larger, with a 15-26 mm wingspan and pale ochre forewings with blackish-brown patches; its larvae eat stored cereals, dried fruit, fabric and fur (Wikipedia). Common in British houses.
• White-shouldered house moth: larvae feed on dried fruit, cereals, wool and old textiles (Wikipedia).
• Carpet beetles: not moths, but the damage looks similar. Their larvae are hairy and leave cast skins instead of silk.

A useful rule: a moth flying readily around the kitchen is more likely a pantry moth, because clothes moths prefer low light and tend to scramble over fabric rather than fly (NHM).

Indoors there is no fixed season: clothes moths breed whenever the house is warm enough. UC IPM gives these figures:

• A female lays an average of 40 to 50 eggs over 2 to 3 weeks.
• Eggs hatch in 4 to 10 days in warm weather; NHM adds up to three weeks in cold weather.
• The larval stage lasts from 35 days to 2 1/2 years, depending on temperature and food.
• Egg to egg usually takes four to six months, which means about two generations a year.

Females lay in quiet, dark, undisturbed places (moth-prevention.com), which is why damage turns up at the back of wardrobes and under heavy furniture first.

Treat the infested item directly. Both UC IPM and the Natural History Museum describe temperature treatments that kill every stage:

• Freeze: seal the item in a plastic bag and freeze for several days below 18°F (UC IPM); NHM gives -20°C for a week.
• Heat: at least 30 minutes above 120°F (UC IPM); NHM gives 49°C for over 30 minutes.
• Wash or dry clean: launder washable items for 20 to 30 minutes in water of at least 120°F, or dry clean them (UC IPM).
• Vacuum carpets, under furniture and closet edges, and empty the vacuum afterwards.
• Store clean woollens in airtight containers (UC IPM, NHM).
• Monitor with pheromone traps; UC IPM notes traps exist for both species. Traps catch males and show whether moths are still around, but they do not end an infestation on their own.

UC IPM also lists pyrethrin-based insecticides for clothes moths; if you use one, follow the label exactly.

Photograph the moth from directly above with its wings at rest, then get the head in focus if you can: the head hair colour is the fastest way to separate the two species. Photograph any larva or case next to the damage and put a coin or ruler in the frame. InsectLens identifies moths and larvae from photos.

Research and drafting for this page used AI assistance. Every figure, date and quotation was then checked line by line against the sources listed at the bottom of the page, each of which was opened while writing. Nothing here is a diagnosis. If a bite, sting or contact with an insect is followed by trouble breathing, swelling of the face or throat, spreading redness, fever or any symptom that worries you, get medical care; in the United States Poison Help (1-800-222-1222) is free and open 24 hours a day.