The purpose of a sticker adjuvant in a spray mixture is to:

• A. Increase viscosity
• B. Neutralize charge
• C. Decrease pH
• D. Increase volatility

Answer: (A)

The main idea is to keep the spray on the target long enough to work. A sticker adjuvant forms a sticky, film-like layer on surfaces, so the droplets cling to leaves or other surfaces rather than bead up and wash off or blow away. This sticky film effectively increases the residue time by making the deposition more viscous and adherent, which helps the pesticide stay in place through wind, rain, or irrigation. That persistence is the key benefit. Neutralizing charge, changing pH, or increasing volatility wouldn’t promote sticking to the surface; in fact, those effects could reduce retention or promote faster loss. So the purpose is to increase adhesion by forming a viscous, sticky film on the target.