What occurs at the point of runoff?

Runoff refers to the water that flows over the ground surface when it is unable to infiltrate into the soil. This situation typically occurs when the soil is saturated, or when there is an excess of water, such as from rainfall or irrigation. In the context of pesticide application, runoff can happen when the spray starts to drip from the foliage of treated plants or from the surfaces of animals that have been treated. This means that the pesticide solution is unable to adhere properly to the target surfaces, leading to potential contamination of other areas as the excess liquid moves off the intended application site.

In this case, the correct choice highlights a specific moment in the pesticide application process where unintended movement of the chemical occurs, which can have implications for environmental health or pest control effectiveness. Understanding this concept is critical for effective pesticide management and ensuring compliance with environmental safety standards.