As with many problems, the best solution is generally prevention. Don't let wood on the outside of your house touch any other sources of wood, such as logs or wood chips. You also don't want wood touching soil directly. Beef up your defenses in trouble areas with sand barriers or metal shields, which can be installed by a qualified specialist.
If you do find that you're sharing your home with unwanted guests, hire a greener exterminator. A number of regions are now served by those who advertise the service specifically, but you also may be able to encourage a conventional exterminator to try some less-toxic approaches. Common treatments now include use of nematodes (microscopic worms) that kill termites, for instance.
Boric acid bait blocks can also be used to cut down on the amount of chemicals needed, versus widespread spraying. Drywood termites can now be treated with thermal, freezing or electrical eradication or desiccating dusts.
