Which adjuvant is used to reduce surface tension and improve spray coverage?

• A. Buffer
• B. Extender
• C. Surfactant
• D. Anticoagulant

Answer: (C)

Surfactants lower the surface tension of the spray solution, which helps droplets spread out and wet leaf surfaces more completely. When droplets can spread into a thin film rather than bead up, coverage across the leaf is more uniform, improving contact with the plant tissue and the effectiveness of the pesticide. Buffers keep pH stable and don’t change surface tension. Extenders are about increasing coverage area or spray volume, not primarily about reducing surface tension. Anticoagulants are unrelated to spray performance. So the adjuvant that reduces surface tension and improves spray coverage is a surfactant.