Target Pest Biology and Fumigation Decision-Making
Identify first, then decide
Fumigation is a whole-structure treatment with no residual protection, so the decision begins with correct identification and a determination that fumigation is the right tool. Drywood termites (for example Incisitermes and Kalotermes species) live entirely in wood and are classic fumigation targets. Subterranean termites nest in soil and reconnect after the gas clears - fumigating a structure for subterranean termites is a well-known wrong answer; soil treatment or baiting is appropriate. Wood-boring beetles (powderpost beetles, old house borer, deathwatch beetles), bed bugs, cockroaches in heavy infestations, stored-product pests, and clothes moths are also candidate targets depending on the situation.
Life stages and tolerance
Susceptibility varies by stage. Eggs of many insects, including stored-product moths and beetles, are more tolerant than larvae or adults, so the label's exposure period - not just the rate - is what delivers control. Termite eggs and reproductives deep in galleries are the reason structures are treated as a whole rather than spot-treated.
Environmental modifiers
Insects respire faster when warm and humid, taking up gas more quickly; cold structures slow both insect metabolism and fumigant volatilization. Sorption by large commodity loads or green lumber removes gas, and tightly packed stacks shield the interior from circulation. These factors push you toward the high end of the labeled rate and the long end of the exposure window.
Decision traps
Fumigating for a pest that will reinvade from outside; promising residual protection; choosing fumigation when a localized treatment (wood injection, heat, removal and replacement) would suffice; and ignoring moisture or decay that makes the structure unsuitable for tarping.
Rule of thumb: if the colony or infestation source survives outside the treated envelope, fumigation alone cannot solve the problem.