Can Carpet Moths Destroy Wool Carpets?

What They Can Actually Do

A sustained infestation grazes the pile down to the backing over a continuous area, and once the pile is gone it does not come back. In a bad case the backing itself is exposed and weakened, and the carpet is finished in that area.

We regularly see this under wardrobes and beds that have not been moved in years, along the edges of spare rooms, and under fitted furniture. It is unusual to see it in the middle of a used room, because being walked on prevents it.

How Long It Takes

Longer than people assume. The larval stage lasts months, and in a cool room it can extend well beyond a year. Serious damage is generally the result of two or three generations in the same undisturbed spot.

Which is the good news: this is a slow problem, and finding it at the thin-patch stage usually means the carpet is saveable. It is also the bad news, because slow means it happens without anyone noticing.

What Makes It Worse Faster

Warmth speeds the cycle up considerably, so a heated house, underfloor heating, or an area above a boiler or beside a hot pipe will show damage sooner. Humidity helps them too.

And soiling. Larvae do better on wool that carries body oils, food residue, pet hair or perspiration, which is why stored unwashed woollens suffer badly and why the carpet under a pet bed goes first.

Wool Mixes, Underlay and Synthetics

Pure wool is the most vulnerable, wool-rich mixes only slightly less so. A wholly synthetic carpet is not food — if something is damaging one, look for a different cause.

But check the underlay. Old felt or hair underlay under a modern carpet is keratin, and larvae feeding on it from below will damage the carpet above without ever being visible on the surface. That is the case people miss.

Whether Yours Is Saveable

A thin patch with the pile grazed but the backing intact is usually treatable, and the carpet stays. Exposed backing over an area is not recoverable in that patch, though the rest of the carpet often is.

Either way, treat before you replace. Fitting a new wool carpet into a room with a live population is an expensive way to feed them, and the treatment is £180 for the first room and £60 for each additional one.