Fumigation

Drywood Termites live inside wood and do not make contact with soil. They get the moisture they need to live from humid air. All drywood termite control methods can be categorized as either whole-structure or localized. A whole-structure treatment is defined as the simultaneous treatment of all infestations, accessible, and inaccessible in a structure.Whole-structure treatments have an advantage over spot treatments in that they are detection independent. This means whole-structure treatments, if applied properly, can eliminate all infestations, even hidden ones.

Powder post beetles include several small, brownish, dry wood-eating insects ranging in size from one-twelfth to one-fifth inch long.
The sooner these insects are controlled, the better. Delay only makes the damage greater. Fumigation may be advisable in cases of severe powder-post beetle damage, especially where other methods have failed or where rapid elimination of the insects is desired. Furthermore, fumigation has advantages where it is hard to apply other treatments, especially in cramped 
crawlspaces or other space-limited areas.

An infestation of old house borers is evidenced by the presence of the adults, their emergence holes, or by the larvae and larval tunnels in the wood. In situations where spot treatments have failed or in serious infestations where there are large numbers of beetles throughout the structure, fumigation may be the best control option. The penetration of fumigants can kill wood-boring beetles in all areas of the structure.