Which of the following is NOT a pesticide?

The correct answer is that a fertilizer is not classified as a pesticide. Pesticides are substances intended for preventing, destroying, repelling, or mitigating pests, including insects, weeds, fungi, and other organisms that can cause harm to crops and health.

A plant defoliant, which is designed to remove leaves from plants, is categorized as a pesticide because it is used specifically to affect plant physiology for pest control purposes. A disinfectant, meant to kill bacteria or viruses, is also considered a pesticide since it serves to manage harmful organisms in various environments.

Fertilizers, on the other hand, are substances added to soil or plants to promote growth and provide essential nutrients. They do not have the primary function of controlling pests, which distinguishes them from pesticides. Consequently, the inclusion of fertilizers in this context highlights their fundamentally different purpose, reinforcing why this option is the one that does not meet the definition of a pesticide.