Sure it can help, but you need to kill all the colonies, not just those that are easy to find, so structural fumigation wins. Orange oil (d-limonene) is a solvent (much like turpentine) which is extracted from citrus peel. You have probably used in to clean your shower. Injected into wood, it will damage the insect's waxy coating if it contacts the insects in sufficient quantities. It doesn't last, but evaporates away. Some companies and one California newspaper scribe, are promoting it heavily. Only useful for drywood termites, not subterranean termites nor probably dampwood termites. If you do want a 'spot treatment' option, then the borate systems provided by Nisus Corp are probably a surer bet since they provide an ongoing residue against re-infestation (which fumigation, obviously, can't).