Insect decay

Beetles and termites

There are number of insect species found in buildings but beetles are the most destructive, causing serious damage to building timbers. Beetles can use wood as a food source and most of the wood boring insects will attack only damp wood.

Death-watch beetle

Death-watch beetle (Xestobium rufovillosum) has a preference for wood that is already pre-digested by fungal attack. Death-watch beetle is a pest of hardwoods, predominantly oak in historic buildings. It also attacks softwoods, particularly when in contact with infested hardwood and other hardwood that has previously been modified by fungal attack.

Emergence holes and tunnels are circular, 3mm to 4mm in diameter, extensive mainly in the direction of the grain of the wood and produce cream coloured disc shaped pellets (bore dust). Death-watch beetles are not active fliers and are found on or beneath the timbers, window cills and carpets between March and June.

Common furniture beetle - woodworm

The common woodworm or furniture beetle (Anobium punctatum) attack the sapwood band of timbers in buildings and in the natural forest. Infestation is usually detected by emergence holes up to 2mm in diameter. Active infestation produces fresh frass (bore dust), which is cream colour, or the colour of fresh cut wood.

Termites

Termites, otherwise known as white ants, are common in tropical and subtropical areas but are also found in temperate regions. So far they are not known in the UK except some isolated outbreaks in Devon and Cornwall, but they do exist in France and Germany.

There are many species known. They fall into 2 distinct categories:

  1. Subterranean termites are the most widespread type and are responsible for most of the damage. They nest out of doors and travel in mud tunnels, which they build over surfaces to reach wood. Houses need careful design to prevent this tunnel building or else the surrounding soil needs to be poisoned.
  2. Dry wood termites never enter the ground. They live in dry wood only; the infestation is started by winged forms laying eggs in cracks and joints of structural timber and furniture. An intact skin is left on the surface, so again attack can be severe but not noticed until collapse occurs. Only preservation techniques will protect wood. Some species of timber are naturally resistant but the resistance varies in different countries, according to the species of termite that lives there.