A pesticide's formulation is its:

The correct answer is that a pesticide's formulation refers to the mixture of ingredients that make up the pesticide product. This includes the active ingredient(s), which are responsible for controlling the pests, as well as various inert ingredients that help stabilize the product, facilitate application, and enhance its effectiveness.

Understanding the formulation is essential because it affects how the pesticide performs, its safety for users and the environment, and how it should be applied. For example, the formulation can determine whether the pesticide is in liquid, granular, or aerosol form, which influences how and where it can be used effectively.

The target pest or purpose, mode of application, and mode of action are all important aspects of pest management, but they do not describe the composition of the product itself. Therefore, while they provide valuable information about how a pesticide is utilized or functions, they do not define the term "formulation."