Small isolated infestations like you may see in a piece of recently purchased furniture can easily be treated yourself using a woodworm killer fluid in a spray bottle. Larger outbreaks in sheds or outbuildings could be tackled with a larger can of woodworm killer and a spray applicator.
Large and extensive infestations are better dealt with by a specialist company, but they will use pretty toxic chemicals to make sure the job is completed at the first visit. Bear in mind that most old buildings will have extinct infestations.
These do not need more treatment; however, some surveyors and parties with vested interests will try to convince you that the insects are active and recommend chemical treatments. If you can't check this for yourself, at least get a second or third opinion.
Woodworm refers to the larvae of the wood-boring beetles of which four species.
The Common Furniture Beetle is a woodland insect, but also loves old houses and old furniture.
Woodworm prefers timber with a moisture content of over 20%. The average moisture content of kiln dried timber used to build new homes is 20% maximum but over the years it will stabilise depending on environmental conditions. This could well be at around 22% over winter and under 20% over summer months. So, woodworm infestation is always a possibility in untreated timbers.