Which of the following is NOT one of the four main types of pesticides?

Fertilizers are substances that are added to soil or plants to provide essential nutrients that promote growth, whereas the four main types of pesticides include fungicides, herbicides, insecticides, and rodenticides. Fungicides target fungal pests, herbicides are used to control unwanted plants or weeds, insecticides target insects, and rodenticides are designed to control rodent populations. Since fertilizers do not serve the purpose of pest control, they do not fit into the category of pesticides, making this option the correct answer. Understanding the distinct roles of these substances is crucial for effective pest management and agricultural practices.