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Pest fact sheet 2: Furniture beetle or Woodworm

This fact sheet can be used for identification of Furniture beetle or woodworm should your collection become affected by pests. Included below are photographs of the adult and larva and information on the life cycle, how to spot signs of damage and the materials likely to be affected and similar species of pest.

Latin name: Anobium punctatum

Identification

The adults are 3mm – 4mm long, dark brown elongated beetles with lines of punctures on the wing cases.

Photograph of an adult furniture beetle emerging from hole
Adult furniture beetle

The head is not visible from above and the thorax is strongly humped. Often confused with the biscuit beetle which is reddish-brown and does not have the hump [see Factsheet 3].

Black and white illustration of an adult furniture beetle from the side
Illustration of an adult furniture beetle from the side

The larvae are 0.5mm – 5mm long and are not normally seen as they live in tunnels in the wood. They are white and strongly curved in a C shape with short legs.

Magnified photograph of a furniture beetle larva. It is white and strongly curved in a C shape with short legs.
The larvae of a furniture beetle

Life cycle

Adult beetles will lay eggs in cracks or end grain. When the larvae hatch, they tunnel into the wood. They live their whole life inside the tunnels which get larger as they grow. The eggs and young larvae will not survive if the wood is below 12% moisture content or the relative humidity is below 55%. The larvae may take 2 to 5 years to complete their growth and then they pupate near the surface of the wood. The adult bites its way out in Spring or early Summer making a characteristic 1.5 to 2mm diameter round exit hole.

Signs of damage

Emergence holes in wood. Old holes will look dark and dirty. New holes will look fresh and sharp. Fresh holes will have piles of bore dust called frass underneath. Frass pellets feel gritty and are wheat grain shaped when magnified.

A piece of wood with dark damage holes in it made by a furniture beetle
Historic damage holes made by a furniture beetle
A piece of wood showing recently made holes by furniture beetle
Recent damage to wood made by a furniture beetle
A small mound of frass from an exit hole made by the furniture beetle
Frass from the exit hole made by a furniture beetle
Magnified image of frass pellets from the exit hole made by a furniture beetle
Magnification of frass pellets from the exit hole made by a furniture beetle

Materials damaged

They will attack many hardwoods which have high levels of starch and sugar. Ash, beech and elm and oak sapwood are attacked but sound oak heartwood is not at risk.

An image of wood with lots of damage holes visible in it that have been made by the furniture beetle
Damage to wood made by the furniture beetle
A piece of oak showing damage holes in the lighter sapwood but not in the dark heartwood
Damage holes from a furniture beetle in the lighter sapwood of a piece of oak but not in the darker heartwood.

Oak sapwood has been attacked, dark heartwood is undamaged. They will readily attack old plywood with animal protein adhesive.

An image of lots of small piles of frass from exit holes made by the furniture beetle in pieces of wood
Piles of frass from exit holes in wood made by the furniture beetle

Is the infestation active?

This can sometimes be very difficult to establish. Holes do not mean that the infestation is active. If the wood is dry and the relative humidity is below 55%, then the infestation is probably longdead. Look for fresh frass and new adult beetles in the Spring near undisturbed objects or timbers. Old frass will often fall out of cracks and emergence holes when objects are moved or dry out. Old frass is not a sign of active infestation.

Similar woodboring species: Fan-bearing woodborer (Ptilinus pectinicornis), Death watch beetle (Xestobium rufovillosum).

Date created: 2010

Author: David Pinniger

Publisher: Collections Trust