Final answer:
A bulb duster should be used for treating voids, such as cracks, crevices, and hidden areas where pests like ants, cockroaches, and spiders are commonly found.
Step-by-step explanation:
A bulb duster is used for treating voids. It is a tool that allows you to apply pesticides or dusts in hard-to-reach areas such as cracks, crevices, and voids. These areas are common hiding places for pests like ants, cockroaches, and spiders. By using a bulb duster, you can distribute the pesticide or dust evenly and reach places that may be difficult to treat with other methods.