Which adjuvant is intended to increase the deposited proportion of spray?

The correct choice is deposition aids, as these adjuvants are specifically designed to enhance the amount of pesticide that adheres to the target surface after application. By improving deposition, they help ensure that more of the active ingredient remains on the plant or pest, which can lead to better effectiveness of the pesticide.

Deposition aids work by altering the physical properties of the spray droplets, such as size and distribution, to promote better coverage and adhesion. This is particularly important in situations where weather conditions, like wind or rain, could potentially remove the pesticide from where it has been applied.

While other adjuvants play important roles in pesticide application, they have different functions. Defoamers, for example, are used to reduce unwanted foam in spray mixtures, which can hinder the application process but do not contribute to managing the amount of pesticide that lands on the target. Compatibility agents help ensure that pesticide mixes do not separate or degrade, allowing for a more uniform application but not specifically enhancing deposition. Stickers are intended to improve the staying power of a pesticide once it is applied, but they do not necessarily relate to increasing the proportion of spray that lands on the intended targets during the application process.