Which term describes pesticides that remain active for an extended period after application?

• A. Systemic Pesticides
• B. Contact Pesticides
• C. Non-Selective Pesticides
• D. Residual Pesticides

Answer: (D)

Understanding how long a pesticide stays active after application. Residual pesticides are designed to leave active residues on treated surfaces, soil, or plant material that continue to control pests days or weeks after you apply them. This lasting effect is what makes them residual—the pesticide remains present and effective beyond the initial treatment.

In contrast, systemic pesticides are taken up by plants and move within their tissues, providing protection by affecting pests that feed on the plant, but their persistence is within the plant rather than as an enduring surface residue. Contact pesticides kill pests on direct contact and often don’t provide long-lasting residual activity. Non-selective refers to broad-spectrum action, not how long the product remains active.