Roller and rope-wick applicators are used to target weeds taller than the desired vegetation by applying at a set height.

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

Answer: (C)

Targeting weeds by height is best accomplished with roller and rope-wick applicators because they deliver herbicide directly to plants that stand above the desired vegetation by applying at a set height. As you move the applicator, the roller or the wick contacts the taller weed foliage while shorter, desirable vegetation is shielded by its lower height, reducing damage to the crop and limiting drift. This height-specific, contact-type delivery concentrates the chemical where it’s needed and minimizes non-target exposure. Other applicators aren’t designed for this height-based, selective delivery: aerosol sprayers blanket an area with a fine mist and can drift onto non-target plants; duster sprayers spread powders rather than liquid herbicide on leaf surfaces; tree injectors place chemical into tree tissue rather than targeting ground-level weeds among vegetation.