Which type of application is designed to dry out insects and remove their wax layer?

The correct choice is desiccant dust, which is specifically formulated to target insects by drying them out and removing their protective wax layer. Desiccant dust works by absorbing moisture from the insect's body, leading to dehydration and ultimately death. This mode of action makes it particularly effective against a variety of crawling insects such as cockroaches and ants.

In contrast, liquid sprays often rely on chemical agents that can cause immediate neurological effects or provide a quick knockdown of pests but do not specifically focus on dehydrating the insects. Foam treatments provide a different approach by expanding within target areas to reach hidden pests, while granular bait is intended to attract and poison insects, rather than drying them out. Each of these alternatives has its own distinct purpose and application method, which differentiates them from the desiccant dust that serves the specialized function of desiccation.