There are many types of wood boring insects which may potentially cause damage to the structural timbers of any building provided that the right conditions and wood type are available. It is often stated that any buildings incorporating wood as the main structure or for flooring over 50 years of age is highly likely to be affected by woodworm infestation. Again there are many factors to be considered before such a bold statement can be deemed as factual.
The most common attacker here in the U.K. is the "Common Furniture Beetle." (Hence the name!) For those people who like to be technical, they can refer to it as Anobium punctatum. They prefer to dine on the sapwood of both soft & hardwoods. They have been known to indulge on the inner heartwood, but only if the area has been broken down by other predators including fungal decay.
It is known that the eggs are laid in clusters in the little cracks, crevasses, and even old flight holes of the timbers they inhabit. The female can lay an average of 28 eggs in one sitting. In the right conditions, these eggs can hatch within 2 - 3 weeks and the whole process starts again.
Most people first notice woodworm attack by the presence of the "exit" or "flight" holes as seen on the photograph (Fig 1a). If left to their own devices, they can cause considerable damage over a period as you can see. You can also find the carcasses of the adult beetles on windowsills or in spider webs beside a window during the flight season (May to September, again depending on conditions).
People lay the blame on the adult beetle (Fig 1b) causing the damage by their bad chewing habits when, in fact, it is the young larva or "woodworm" (Fig1c) feeding and carving the tunnels with their strong jaws. This part of the cycle can last up to 3 years.
Treatment - There has been a variety of treatments experimented with over the years ranging from flight hole injection to fogging or smoke bombs to freezing/heating. Each one has its own merits. The most commonly used in general-purpose terms is the coarse spray application. But it is the type of solution that counts!