Holes in clothes from moths: how to tell

Moth holes in wool knitwear are irregular holes where the yarn has been chewed clean through, according to a CSIRO Textile and Fibre Technology guide. CSIRO's Australian National Insect Collection explains that the damage is done by the clothes moth larva, not the adult moth, which does not eat at all.

What a moth hole looks like

A CSIRO Textile and Fibre Technology guide describes damage to fine knitted goods as irregular holes where yarns have been completely severed and eaten, much like the damage small caterpillars do to plant leaves. Where the material is not entirely palatable, CSIRO's guide notes the larva sometimes feeds only on the surface nap, so yarns are partly severed and no hole appears. In either case, CSIRO says insect debris such as droppings or silk threads sits around the damaged area.

A knitted garment shows visible damage from relatively few larvae, or from the larvae hatched from the eggs of a single female moth, according to CSIRO's guide. CSIRO describes the droppings as 1.0 mm to 1.5 mm, brittle like coarse sand, usually the same colour as the fabric being eaten, and often mistaken for eggs.

Signs of clothes moths

CSIRO's insect collection and Textile and Fibre Technology guide record these signs.

• Adult clothes moths are buff coloured and about the size of a large grain of rice.
• Some clothes moth larvae carry a case made from fibres and their own faeces.
• The webbing clothes moth Tineola bisselliella and case-making clothes moth Tinea pellionella are the best-known Australian clothes moths; the adults are 4 mm to 9 mm long.
• Clothes moth larvae are cream with a brown head; the webbing larva feeds inside silk tunnels and the case-bearing larva lives in a small case.
• Carpet beetle larvae also eat wool and leave cast skins; their bodies have stiff bristles.

Which knitwear is most at risk

CSIRO's 2022 article explains that clothes moth larvae feed on keratin, a protein in natural fibres, favour animal fibres such as wool and silk, and have been known to feed on synthetic and blended fibres, particularly ones stained with sweat or food. Unwashed clothes that hold some moisture suit clothes moths particularly well, and the larvae prefer dark places, says CSIRO's 2018 article. A CSIRO Textile and Fibre Technology guide says wool in frequent use and regularly washed or dry cleaned is unlikely to be damaged unless there is an infestation nearby, while untreated woollens left in cupboards for several months are more prone to damage. The guide How to store wool jumpers covers keeping stored jumpers safe.

After you find one

CSIRO's advice on seeing clothes moths near clothes is to wash the clothes and air them in the sun. Safe washing steps for wool are covered in How to wash a wool or merino jumper. For readers who want to repair the hole, Woolmark's darning method is explained in How to fix a hole in a jumper.

Knit-On Australia has two shops: Melbourne CBD at 520 Bourke Street and Ripponlea at 79 Glen Eira Road, open 10am to 6pm every day. Public holiday hours vary. Staff give care advice in both. The Wool Knitwear page shows 116 products priced from $49 to $499 AUD.

Common questions

Do moths themselves eat holes in clothes?

Adult clothes moths do not eat at all, according to CSIRO's Australian National Insect Collection. The larva chews the damage with jaws called mandibles, and CSIRO notes those jaws work on wool, felt, silk and fur.

What do moth droppings look like on clothes?

CSIRO's Textile and Fibre Technology guide describes them as 1.0 mm to 1.5 mm, brittle and like coarse sand. CSIRO notes they usually match the colour of the fabric the larvae are eating, and people often mistake them for eggs near the damaged area.

Are small holes in a jumper always from moths?

Carpet beetle larvae also eat wool, so moths are not the only insect behind small holes. CSIRO's Textile and Fibre Technology guide says moth damage is usually irregular holes with completely severed yarns, or surface grazing with no hole plus debris near the area. Carpet beetle larvae have stiff bristles and leave cast skins, CSIRO notes.

Why do moths go for wool jumpers?

Keratin in natural fibres draws clothes moth larvae, and CSIRO's 2022 article names wool and silk as favoured animal items. CSIRO's 2018 article says the larvae do well in unwashed clothes that hold some moisture and prefer dark places.