Which adjuvant type is primarily used to keep the pesticide on leaf surfaces?

• A. Sticker
• B. Surfactant
• C. Penetrant
• D. Drift control agent

Answer: (A)

Keeping the pesticide where you want it means maximizing stay-on-leaf retention, resisting being washed or blown off. A sticker adjuvant does exactly that by forming a light, enduring film on the leaf surface that helps the spray adhere and remain where it was applied. This keeps the product on the leaf longer, improving efficacy, especially in conditions with rain, dew, or wind. Surfactants focus on wetting and spreading to improve coverage but don’t inherently prevent wash-off. Penetrants aim to move the pesticide into the leaf tissue for systemic action, not to stay on the surface. Drift control agents reduce off-target spray in the air, not surface adhesion. So the sticker is the adjuvant type that best keeps the pesticide on leaf surfaces.