Why are systemic pesticides effective for certain pests?

• A. They stay on the surface
• B. They translocate to distant tissues within the plant or animal
• C. They evaporate quickly
• D. They require pre-emergent conditions

Answer: (B)

Systemic pesticides work because the active ingredient is absorbed and moved through the plant’s or animal’s internal transport system, so it travels to tissues far from where the product was applied. This internal distribution means pests that feed inside plant tissues—such as sap-feeders or pests on new growth—encounter the toxin even if the application site isn’t right where the pest feeds. That’s why systemic products are especially effective for pests that hide inside stems, leaves, roots, or new growth, or for pests that move through the plant to feed. In contrast, a surface residue would only affect pests that come into contact with that surface, and a volatile or quickly evaporating product would disappear before it can reach pests elsewhere. Pre-emergent conditions relate to weed control timing, not how a pesticide moves within a plant or animal.