Insect Damage
Recognising the damage, identifying the cause and the insect responsible
Correctly identifying the insect responsible for damage is an essential first step to monitoring and trapping the offenders. Often however, no insect may be found and there is only damage to be observed such as holes in clothing and bare patches on carpets.
In other cases, adult insects may be found but it is the larval (caterpillar) stage that does the damage and so seeing or catching the adults can be an early indication of future damage likely to appear.
The following table provides a quick assessment of some of the most common places that damage may be observed and how to determine which pests are responsible
Damage
Ragged ‘messy’ holes with silk-like threads and pinhead size balls of frass (the same colour as the fabric).
The Culprit
Webbing Clothes Moth larvae – small, white larvae with dark heads.
Adults
Small, silvery-gold moths often running over the material.
Webbing Clothes Moth (Tineola bisselliella)
Damage
Ragged holes some ‘frass’ often small, cream-coloured pupae cases resembling flattened grains of rice.
The Culprit
Case-bearing Clothes Moth larvae, white with dark heads.
Adults
Same as Webbing Clothes Moth, but darker wings.
Case-making Clothes Moth (Tinea pellionella)
Damage
Small ragged holes, no frass often ‘cast skins; (small, bristly brown shells).
The Culprit
Carpet Beetle larvae (woolly bears) – small brown hairy larvae, active.
The Adult
Small, oval beetles (like tiny ladybirds) with coloured patterning.
Varied Carpet Beetle (Anthrenus verbasci)
Damage
Small ragged holes, no frass often ‘cast skins; (small, bristly brown shells).
The Culprit
2-Spot Carpet Beetle larvae, as left, but with long bristly ‘tail’.
The Adults
Small, shiny, black oval beetle with two white spots on its back.
Two-Spot Carpet Beetle or Fur Beetle, (Attagenus pellio)
Damage
Grazed areas on paper with small holes, minute teeth marks visible around holes.
The Culprit
Silverfish: Small, thin silvery fast-moving insects. They avoid the light.
The Adult
Associated with damp, dark areas.
Damage
Grazed areas on paper and bindings.
The Culprit
Book lice: Pinhead sized grey-brown insects. Fast moving and avoid light.
The Adult
Associated with damp, dark areas.
Damage
Small (2-3mm) holes with pale insides. Often pale, gritty frass coming out.
The Culprit
Furniture beetle (woodworm) larvae. Seldom seen.
The Adult
Small, brown, slim beetles (4-6mm long) with grooved wing cases and hooded head.
Damage
Large (4mm) holes in oak, often with reddish, gritty frass.
The Culprit
Deathwatch beetle larvae. Seldom seen.
The Adult
Smallish, fat beetles, grey-brown with lighter patches on wing cases and hooded head. Often found on the floor below oak beams etc.
