Define “residual activity” of a pesticide.

Residual activity of a pesticide refers to the duration of its effectiveness after application. This means how long the pesticide remains active in the environment and can effectively control pests after being applied. Understanding residual activity is crucial for pest management because it helps determine how often treatments should be applied to maintain effective pest control.

Factors that can influence residual activity include the pesticide's formulation, environmental conditions, and the target pest. This information aids in planning applications to achieve optimal pest control while minimizing unnecessary exposure to non-target organisms and the environment. Choices regarding the cost, timing before application, and the application method do not provide insights into the duration that the pesticide remains effective, which is the key aspect addressed by the concept of residual activity.