Woodworm

A term used for the destructive larvae of the Common Furniture Beetle.

First sign of woodworm is the appearance of neat round holes, 2mm across, in wooden surfaces, often accompanied by tiny piles of wood dust beneath them. Fresh holes show clean white wood inside. The holes are made by emerging adult beetles, immature grubs may still be tunnelling away inside the wood.

The adult Furniture Beetle is a small brown insect 3mm to 6mm long which flies quite readily. It lays eggs on rough, unpolished wood and the grubs bore straight into the wood – leaving no trace until they emerge as beetles three years or so later, usually between May and September.

Woodworm is frequently introduced into the house in second-hand furniture, tea chests or wicker-work; but the beetles are quite capable of flying in through a window from nearby dead branches of trees. They may then attack floorboards, joinery and, more seriously, structural timbers such as rafters and joists.

Other woodborers include: Death Watch Beetle, which infests only large old hardwood beams; the House Longhorn, confined – at least for the moment – to North West Surrey; Powder Post Beetle which needs a diet of starch in certain hardwoods, and woodboring weevils, which are associated with wet rot and die out when it is treated.

REMEDY Woodworm in furniture can be cured by application of proprietary woodworm killer. Coat all surfaces, polished and unpolished, and inject fluid into a few flight holes with a special injector. As a precaution against woodworm, you can buy an insecticidal polish.

Woodworm in structural timbers can be treated on a do-it-yourself basis and the proprietary fluids used by the experts are available from builders merchants. All timbers must be cleaned down first and any roof insulation material will have to be removed temporarily so that you can get at the joists to work on them. Also this avoids the fire-risk of insulation becoming impregnated with the fluid or small polystyrene granules dissolving together.

Cover electric cables and the cold water storage tank. Floorboards must be lifted to get at the undersides and the joists. Follow label recommendations carefully. Detailed surveys, reports and estimates are given by specialist wood preservation companies from the British Wood Preserving and Damp-proofing Association. Many cover their treatments by long term guarantees – useful evidence of treatment if you want to sell the house. It is usually wise therefore to leave structural woodworm to the experts.