Persistent pesticides remain sufficiently active to kill pests for days, weeks, or months after application. What is this class called?

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

Answer: (B)

The idea here is pesticides that keep working long after they’re applied, providing ongoing pest control. Pesticides with residual activity remain active on treated surfaces, in soil, or on plant parts for days, weeks, or even months, so pests that encounter them later are still affected. This lingering effect is what defines them as residual pesticides.

This differs from systemic pesticides, which are absorbed and moved inside the plant to protect against pests that feed on it, rather than staying on a surface to kill pests later. Contact pesticides kill pests through direct contact at the time of application and often have shorter lasting effects. Non-selective refers to broad pest range, not how long the product remains active.