Why Does Carpet Moth Damage Often Appear Under Furniture?

The Larva Is Fragile and Slow

It is the larva that eats the carpet, and it feeds slowly over weeks or months, grazing the pile down towards the backing while staying in contact with it. It is small, soft and easily dislodged, and it does not travel far.

Anything that disturbs it — being walked on, being vacuumed, light, air movement — interrupts feeding or removes it entirely. So the population survives in the places where none of that happens, and those places are underneath and behind things.

Which Is Why the Damage Maps the Furniture

Lift a wardrobe that has stood in the same corner for eight years and the damage is often shaped like the wardrobe. Move a sofa and the thin patch stops in a line where the base was. It is the clearest damage pattern in this trade.

It also explains why room edges suffer: the last few inches before the skirting are walked on less than anywhere else, and the carpet edge over the gripper is dark and undisturbed underneath.

The Diagnostic Value of That

It is how you tell moth damage from wear. Wear happens in the traffic lanes, is roughly symmetrical and follows the routes people take. Moth damage is the inverse — it appears exactly where nobody goes, and it has a soft irregular edge rather than a worn-in one.

So when someone tells us the carpet is fine in the middle of the room but going in the corner behind the chair, that is close to a diagnosis before we arrive.

Vacuuming Is Not Housework Here, It Is Control

Because disturbance is what limits them, regular vacuuming of the places they can survive is a genuine control measure rather than a tidiness measure. Under the beds, under and behind the sofa, the carpet edges, inside wardrobe floors, and the carpet under any rug.

Use the crevice tool along the gripper line at the room edges. That strip is where the eggs, the cases and the debris collect, and a wide vacuum head passes straight over it.

The Prevention That Actually Works

Move the heavy furniture once or twice a year and vacuum under it. That is the whole preventive programme and it costs nothing. Everything else — sprays, deterrents, sachets — is less effective than simply not letting a corner of your house sit undisturbed for five years.

And check before you buy: wool, silk, fur and feather are food, synthetic fibre is not. A synthetic carpet over a wool underlay can still be attacked from below, which catches people out.