Bald Patches in Carpets in Windsor: Could Moth Larvae Be Responsible?

Four Things That Make a Bald Patch

• Traffic wear. Gradual, in a path, worst at doorways and the turn at the bottom of a staircase
• Furniture crush. A flattened rectangle with sharp edges, matching a foot or a base. The pile is compressed rather than missing
• Sunlight and age. Fading and brittleness, usually in a window's footprint, with the pile thinning evenly
• Moth larvae. Irregular, patchy, with the pile grazed away and the backing showing through in places

The first three are the carpet's history. The fourth is a live problem, and it is the only one that keeps getting worse if nothing is done.

The Test That Separates Them

Position, before anything else.

• Wear happens where people walk. Doorways, the middle of a room, the line from door to fireplace, the outside of a stair turn
• Moth damage happens where they do not. Under the bed, behind the wardrobe, along the skirting, under a rug, in the corner of a room nobody uses
• A bald patch in the middle of a busy room is almost certainly wear
• A bald patch under something is almost certainly not

What Else To Look For In the Patch Itself

• Fine silky webbing, sometimes with grains of debris caught in it. Wear does not produce this
• A sandy or gritty debris in and around the patch
• Small cream larvae, often inside a case the colour of the carpet, which is why they are easy to miss
• Loose fibre lying free rather than compacted down
• Backing visible in patches rather than evenly

On a Rug, Which Is Different

In a period house a good deal of the wool is in rugs rather than fitted carpet, and rugs show this differently.

1. Turn it over. Most rug damage starts on the underside, against the floor, where it is dark and still
2. Look for the foundation showing. On a hand-knotted rug the larvae take the wool pile and leave the cotton or wool warp and weft standing — a bald area where you can see the grid of the foundation
3. Check the parts under furniture, and the section that sits under a sofa or a cabinet
4. Check the fringe and the selvedge, if either is wool
5. Look at the floor underneath, which is often where the debris is

A rug that has been in the same position for years, with a bald area on the covered part and none on the exposed part, is not worn. It has been eaten.

The Pencil Test, Which Settles It

1. Photograph the patch with something for scale beside it
2. Mark the edge in pencil, or lay a line of pins along the boundary
3. Write the date
4. Look again in four to six weeks
5. If it has grown past the mark, something is feeding. If it has not, it is history

Treatment starts from £220. If you are unsure, photograph it and mark it before you do anything else — it costs nothing and it answers the question better than any description.