Which action is recommended for inaccessible areas with drywood infestations?

Fumigation is the recommended action for inaccessible areas with drywood infestations because it allows for the complete eradication of pests in enclosed spaces where direct application of treatments is not feasible. Drywood termites can live deep within structural components and their colonies can be hidden from sight, making other control methods less effective. Fumigation involves sealing the infested area and introducing a gas that penetrates all areas, eliminating pests throughout the entire treatment zone.

This method ensures that all life stages of the pests are targeted, including eggs, nymphs, and adults, providing a comprehensive solution to the infestation. Fumigation is particularly effective because it treats areas that are otherwise unreachable by topical treatments or localized spot treatments. Other options, such as allowing natural predators to manage pests or treating only adjacent accessible areas, may not adequately address the infestation in inaccessible regions. Monthly inspections could enhance monitoring efforts but would not resolve existing infestations.