How are pesticides best defined?

The best definition of pesticides is that they are agents that kill, hurt, or repel unwanted organisms. Pesticides are specifically designed to control pests, including insects, weeds, fungi, and other organisms that can harm crops or threaten human health. They work by targeting the specific biology of these organisms, often disrupting their life processes or causing mortality. This distinction is essential for understanding the role of pesticides in agriculture and pest management, as their primary function is to protect crops and resources from various types of pests.

In this context, other options misrepresent the concept of pesticides. Substances that promote plant growth refer to fertilizers rather than pesticides, which are aimed at pest control rather than plant enhancement. Natural products used in farming could describe a wider range of substances, including organic farming methods that may not necessarily include those that kill or repel organisms. Compost materials for soil enrichment focus on improving soil quality rather than targeting pests, distinguishing it from the primary function of pesticides. Thus, the definition as agents that kill, hurt, or repel unwanted organisms accurately captures the essence and purpose of pesticides in agricultural practices.