The short answer
Clothes moth eggs are tiny, white, oval and about the size of a pinhead, laid in batches of 40 to 50 and glued to the fibres of wool, silk, fur or feathers. They are very hard to see with the naked eye. In a heated home they hatch in about a week to ten days, and freezing, a hot wash or heat treatment kills them.
You have found holes, maybe a few small moths, and now you want to know whether there are eggs in your clothes. The honest answer is that you will probably not see them. But knowing what they look like, and where they are laid, tells you what has to be cleaned or treated.
What clothes moth eggs look like
The eggs of the webbing clothes moth, the commonest textile pest in British homes, are:
- Tiny. MuseumPests describes them as pinhead-sized, well under a millimetre.
- White or ivory, slightly oval and smooth.
- Sticky. A gelatinous coating glues them to the threads, so they do not shake off easily.
- Laid in batches. A female lays about 40 to 50 eggs. UC IPM says she lays them over two to three weeks.
Against cream wool or white silk they are almost invisible. On dark navy or black cloth you may, with a magnifying glass and a good light, see what looks like a sprinkling of fine salt grains caught in the fibres.
Where moths lay their eggs
The female does not lay eggs at random. She picks material the larvae can eat, in a place that stays dark. English Heritage says eggs are laid in batches on wool, fur, feathers and skins. In a home that usually means:
- folded knitwear at the back of a drawer or shelf
- suits and coats that hang untouched for a season
- the underside of wool rugs and the edges of fitted carpet
- felt, such as piano hammers and hat linings
- feather cushions, duvets and down jackets in storage
- blankets and throws kept in ottomans and blanket boxes
Soiled items are favoured. A jumper put away with a food mark or sweat in it is more likely to be chosen than a clean one, which is why cleaning before storing matters so much.
How long moth eggs take to hatch
It depends almost entirely on temperature. The MuseumPests fact sheet gives:
| Temperature | Time to hatch |
|---|---|
| About 13°C | Around 37 days |
| Room temperature | 7 to 10 days |
| About 32°C | Around 4 days |
So in a centrally heated London flat, eggs laid this week will be feeding larvae before the end of next week. In a cold loft or unheated spare room they can sit for over a month, which is one reason moths seem to appear from nowhere when the heating comes on in autumn.
Moth eggs or something else?
Several things are mistaken for moth eggs:
- Frass. Larval droppings are tiny grains, often the colour of the fabric the larvae have eaten, and gritty rather than smooth. If you see these, larvae have already hatched.
- Cases. Case-bearing moth larvae leave small silk tubes, a few millimetres to about a centimetre long. These are much larger than eggs.
- Fluff and lint. Little white pills on knitwear are just wear.
- Carpet beetle eggs. These are also tiny and white, but are laid near fluff, nests and dead insects as well as on wool.
If in doubt, put the item in a sealed bag and freeze it. That deals with eggs whatever laid them.
How to kill moth eggs
Eggs are protected by being so small and so well stuck on, so the methods that work are the ones that reach every fibre.
Freezing
English Heritage recommends sealing items in plastic freezer bags and holding them at -18°C for at least two weeks, which kills adults, eggs and larvae. Let the bag come back to room temperature before opening it, so condensation does not form on the cloth.
Hot washing
For items whose labels allow it, a hot wash kills eggs. UC IPM gives at least 20 to 30 minutes in water over about 49°C.
Brushing and airing
UC IPM recommends brushing woollens thoroughly, especially along seams, which dislodges and destroys eggs and exposes young larvae. On a dry day, hanging coats and tweeds outside and brushing them works well for things you cannot wash.
Professional heat treatment
For rugs, upholstery, fitted carpet and rooms full of clothes, a specialist can heat the whole space to a temperature that kills every stage, eggs included. See moth heat treatment in London.
What does not kill eggs
- Pheromone traps catch males only. They tell you moths are present but do nothing to eggs.
- Lavender is safer than old mothballs, but English Heritage says it is not effective on larvae, and it does nothing to eggs already laid.
- Shop aerosols kill adults they hit, but rarely reach eggs deep in fibres.
Why eggs mean follow-up visits
Because eggs can take days or weeks to hatch, a single insecticide treatment rarely catches them all. That is why a professional spray course in London is usually two or three visits a few weeks apart, typically £240 to £330. Our clothes moth treatment page and price calculator explain more.
If you think you have eggs in good clothes or rugs, ask us for a specialist and we will find one who covers your postcode.