Which adjuvant is used to increase the size of spray droplets and decrease the number of fine droplets?

The correct answer is drift control additives. These adjuvants are specifically designed to modify the physical properties of the spray mixture to produce larger droplet sizes. By increasing the droplet size, drift control additives help minimize the number of fine droplets that can be carried away by wind, which reduces the potential for off-target herbicide application. This is particularly important for ensuring that the herbicide reaches the intended target and does not affect neighboring crops or the environment.

Drift control additives achieve this by increasing the viscosity of the spray solution and enhancing the formation of larger droplets during application. This adjustment can lead to more effective control of the target weeds while reducing environmental risks associated with drift.

In contrast, extenders, wetting agents, and inert emulsifiers have different purposes, such as improving the adhesion and spread of the herbicide on the plant surface or modifying the behavior of the herbicide in a solution but do not primarily aim to reduce fine droplets or manage drift.