Which term best describes pesticides that form gases or vapors?

• A. Adjuvants
• B. Solutions
• C. Fumigants
• D. Emulsions

Answer: (C)

Pesticides that form gases or vapors are called fumigants. The key idea is that fumigants release a toxic vapor that can diffuse through air and reach pests in hidden or enclosed spaces, such as soil pores, grain bins, or inside buildings. Because they work as gases, handling them requires strict safety and containment: closed spaces, gas-tight seals, monitoring of gas concentrations, and proper ventilation are essential to protect people and non-target organisms. Adjuvants are additives added to spray mixtures to improve spread or uptake, not pesticides that become gases. A solution formulation means the active ingredient is dissolved in a liquid solvent, so the product remains a liquid rather than a gas. Emulsions are mixtures of two immiscible liquids with an emulsifier, also liquids. So the term that best describes pesticides that form gases or vapors is fumigants.