The term woodworm actually encompasses more than one species of wood boring insect which lay their eggs in wood. The larvae (the worms) feed on the wood as they dig themselves out, leaving a hole and a pile of sawdust as they exit as fully fledged beetles. The whole process can take a number of years. Woodworm beetles are the furniture beetle, the deathwatch beetle, the longhorn beetle and the powderpost. If they find their way inside, wooden structures such as floorboards and beams can be seriously compromised and furniture ruined.
Manageable items should be removed and treated with a woodworm specific spray, designed to soak into the wood and kill the larvae as they eat through it. If the infestation is large or in the house structure, professional help should be sought.