What term is used to describe the active ingredient in a pesticide formulation?

The term used to describe the active ingredient in a pesticide formulation is "toxicant." A toxicant is a specific substance that can cause harm or adverse effects to living organisms when they are exposed. In the context of pesticides, the toxicant is the part of the formulation responsible for the pesticidal activity, meaning it is the compound that affects the target pest, whether it is an insect, weed, or other unwanted organism.

In comparing the other terms, "pesticide" refers to the entire product, which includes not only the active ingredient (toxicant) but also any inert ingredients that may assist in the formulation’s effectiveness or application. "Toxin" is a broader term that generally refers to naturally occurring poisonous substances produced by living organisms. While it can include pesticides, it does not specifically denote the active ingredient in a pesticide formulation. "Insecticide," on the other hand, specifically refers to a type of pesticide that targets insects; therefore, it doesn't encompass all classes of pesticides defined by their active ingredients.

Thus, "toxicant" is the most precise term to denote the active ingredient within a pesticide, focusing specifically on its role and effects.