Here’s a quick list of the main ways to kill or control termites

For Dampwood termites

• Take the moisture away so that they can’t live.
• Replace old, rotted wood with fresh timbers.
• Apply poisons or preservatives into the wood.
• Open up the wood and let the ants eat them.

For Drywood termites

• Fumigation will kill all the termites.
• Tenting and heatng will kill them if everything gets hot enough.
• Extreme cold will also kill them.  For example, an infested yacht can be taken to very cold waters for the winter and furniture and artefacts (if dry) can spend a while in a freezer.
• Spot-treatments with poisons can kill them, but you have to be sure to find, and adequately reach, each and every piece of infested timber.  The risk of error is high.

For subterranean termites

• Killing the colony with direct applications of poisons is the surest approach if you can find the main nest(s).
• If you can’t find nests, but have located leads (shelter tubes) and areas of high activity then applying a very slow-acting non-detectable poison (by dust, foam or liquid) cause it to be shared widely before any individuals die, thus having a good chance of killing the whole colony.
• If you know they’re there but can’t find good numbers, then baits can be used to aggregate large numbers for poisoning.  Commercial bait systems often use very slow acting hormones and it may take weeks or months to see a result.
• Soil poisons to isolate a structure are best left to mopping-up or remedial barrier work but sprays of a non-repellent toxin (like chlorantraniliprole,  fipronil or imidacloprid) can help reduce termite populations and may kill the colony (if you are lucky).
• Very rarely, a nest that is big, obvious and isolated can be physically removed, taking enough of the termites to cause colony collapse.

So, the bottom line is try to get rid of the whole colony as killing a few termites may not make much difference.  Once you have achieved control, it is important to prevent future infestations from the same causes.  For more details, check out the termite FAQs.