How Do You Know If You Have Carpet Beetles?

The Larva Is the Identification

A carpet beetle larva is short, stout, banded light and dark, and covered in bristles. Around 4 to 5mm. It curls up when disturbed and it leaves shed skins behind as it grows, which often outnumber the live larvae you can find.

That bristly, banded, curl-up-when-touched combination is the whole diagnosis. A carpet moth larva is a smooth pale caterpillar, frequently inside a silky case, and looks nothing like it once you have seen both.

The Adult on the Windowsill

This is the one that gets noticed first. Adult carpet beetles are small, rounded and mottled — often described as looking like a tiny ladybird without the bright colour — and in spring they head for the light.

So the classic report is "little beetles on the windowsill of the back bedroom in April". They are heading OUT to feed on pollen, which means they hatched somewhere INSIDE that room or above it.

The Damage Is Scattered, Not Spreading

Small distinct holes in several places rather than one grazed patch. Damage along seams and folds in stored clothing. Bare threads on the underside of a rug. Holes in a jumper that has been in a drawer since last winter.

It also happens where nothing is on show: inside a wardrobe floor, in a chest of drawers, underneath a bed. That scattered distribution is what separates it from carpet moth.

The Place People Forget to Look

Upwards. Carpet beetles very often come from a bird’s nest in the eaves, a dead bird in a chimney or soffit, or a loft with stored wool, feathers and old bedding in it. Any of those keeps producing larvae indefinitely and quietly.

If adults keep appearing on the windowsills of upstairs rooms year after year, the source is very likely above the ceiling rather than in the carpet. Treating the carpet every spring without dealing with that is a subscription, not a solution.

Where to Look Inside

Wardrobe floors and the backs of drawers. Under beds and heavy furniture. Along carpet edges and under the gripper. In airing cupboards. In boxes of stored textiles. Under a rug that sits on a hard floor.

Also lift the carpet edge if you can. Where a house has old felt or hair underlay under a modern carpet, the larvae feed on the underlay and the carpet above looks fine until the damage is well advanced.