Under what conditions is pesticide application the only means for suppressing pests of structures?

Pesticide application becomes the only viable means of suppressing pests when other non-chemical methods are either ineffective, unavailable, or impractical for the circumstances at hand. This situation arises when, despite the potential for various alternative management strategies, they cannot adequately address the pest problem.

For instance, physical barriers might not be an option if structures are already compromised, or biological controls might be hindered by environmental factors. In such scenarios, the urgency to control a pest population to prevent further damage or health risks makes pesticide treatment necessary. Therefore, the decision to resort to pesticide use is often dictated by the lack of feasible alternatives that can effectively manage or eliminate the pest problem at hand.

Other choices suggest conditions that do not align with the necessity of pesticide application. For example, if there are many available non-chemical methods, it implies that you have alternatives to pesticides. Similarly, when a pest is too large to handle, it doesn't inherently suggest that pesticides are the only option, as size alone does not dictate management approaches. Lastly, when infestation levels are low, non-chemical methods might still be sufficient to manage the situation without immediately resorting to pesticides.