Which of the following is NOT considered a pesticide?

Sanitizers are not considered pesticides because they are typically used to clean and disinfect surfaces, rather than to control pests. Pesticides are defined as substances used to prevent, destroy, or repel pests, which includes insects, weeds, bacteria, fungi, and other organisms that may cause harm to crops, human health, or the environment. While plant growth regulators, plant defoliants, and plant desiccants all interact with the physiological processes of plants to promote certain outcomes—such as regulating growth, causing leaf drop, or drying out plant material—they are designed to manage plant health and development rather than specifically targeting problematic organisms. Thus, sanitizers stand apart as they are focused more on sanitation and hygiene rather than pest control, making them the correct answer to this question.