What is the definition of a biocide?

A biocide is defined as a substance that kills biological organisms. This definition encompasses a wide variety of products, including those used in both agricultural and non-agricultural settings. Biocides are designed to target specific pests, pathogens, or other unwanted organisms, effectively controlling or eliminating them through various mechanisms. This aligns with the primary goal of using biocides, which is to manage populations of organisms that can negatively impact health, agriculture, or the environment.

In contrast, options like the substance that repels pests without killing them focus on deterrence rather than elimination, which is not consistent with the function of a biocide. Similarly, a chemical that accelerates plant growth does not pertain to the killing of organisms. Lastly, a formula that enhances the effects of other pesticides refers to adjuvants or synergistic agents but does not describe a biocide's primary role, which is to incapacitate organisms.