Which of the following is NOT a main category of pesticides?

The correct answer is identified as C, allergens, because allergens are not categorized as a type of pesticide. Pesticides are classified primarily based on the types of pests they control.

Insecticides are specifically designed to target and control insect populations, making them essential for managing pest issues in agriculture and horticulture. Herbicides are used to kill or inhibit the growth of unwanted plants, commonly known as weeds. Fungicides are employed to prevent or control fungal infections, which can affect various crops and ornamental plants.

Allergens, on the other hand, refer to substances that can cause allergic reactions in individuals and do not function as pest control agents. They are a different category altogether, related more to health and safety rather than pest management. Understanding this categorization is crucial for proper pesticide use and compliance with regulations governing pesticide application.