Which type of adjuvant physically alters the surface tension of a spray droplet?

Surfactants are adjuvants that are specifically designed to reduce the surface tension of spray droplets. By lowering surface tension, surfactants help the droplets spread and wet the surfaces more evenly, improving the coverage of the pesticide being applied. This increased surface area contact enhances the efficacy of the pesticide by allowing it to adhere better to the target surface, whether that be a plant leaf or another type of material.

While other types of adjuvants, like stickers, plant penetrants, and buffers, serve different functions, they do not primarily focus on altering surface tension. Stickers help to retain the pesticide on the surface longer by reducing wash-off from rain or irrigation, plant penetrants facilitate the movement of chemicals into the plant tissues, and buffers adjust the pH of the spray solution to optimize the pesticide's performance. Each plays a crucial role in pesticide application, but surfactants are unique in their ability to directly modify the physical properties of the droplets themselves.