What is the significance of a pesticide's "first runoff"?

The significance of a pesticide's "first runoff" relates to the evaluation of how effectively the application has penetrated and treated the target plants. This runoff occurs shortly after the pesticide is applied and can indicate how well the pesticide has adhered to the plant surfaces, how much was absorbed, and whether any excess product is being washed away by water. When little runoff is observed, it often suggests that the application was sufficient to cover the plant adequately, ensuring minimal waste of product and maximizing efficacy.

In contrast, while the effectiveness of the application (the first choice) might be indirectly related to runoff, it does not capture the complete picture of how the pesticide interacts with the environment immediately after application. The residual activity of the pesticide and the prediction of its environmental lifespan are more related to how the product behaves over time in the environment rather than the immediate post-application runoff status.