What term describes the continued effectiveness of a pesticide over time?

The term that best describes the continued effectiveness of a pesticide over time is "residual." This term refers to the ability of a pesticide to remain active and exert its effects after application, which allows it to control pests even after the initial application has occurred. Residual activity is crucial in pest management strategies, as it ensures that the pesticide continues to provide protection against target pests for an extended period, reducing the need for frequent reapplication and improving cost-effectiveness.

In contrast to residual, immediate refers to the effects produced by a pesticide shortly after its application, while direct typically describes the manner in which a pesticide impacts a pest upon contact. The term temporary suggests a lack of long-lasting effectiveness, which contradicts the concept of residual activity. Therefore, residual is the correct choice as it encapsulates the aspect of sustained efficacy that is essential for effective pest control.