Duster sprayers are commonly used for small or inaccessible areas such as wall voids.

• A. Hand sprayers
• B. Duster sprayers
• C. Tree injectors
• D. Roller and rope-wick

Answer: (B)

Duster sprayers are designed to deliver dry pesticide dust into tight spaces, which is exactly what wall voids and other small, inaccessible areas require. The fine powder, blown with a stream of air, can reach cracks and cavities where liquid sprays can’t deposit effectively. Because it’s dry, there’s minimal moisture left behind, so the material stays in place on surfaces within the voids and doesn’t drip or run through porous materials. This makes them ideal for pests that hide inside walls or other compact spaces.

Other tools are suited to different tasks: hand sprayers apply liquid sprays that can run or miss voids, tree injectors are for inserting chemicals into trees, and roller and rope-wick systems apply damp coatings to exposed surfaces rather than delivering material into narrow spaces.