When does the greatest pesticide loss from runoff typically occur?

The greatest pesticide loss from runoff typically occurs when rain falls within 24 hours of application. This is primarily because pesticides can take some time to effectively adhere to the targeted surfaces or soil. When rain falls shortly after application, it can wash away these chemicals before they have had a chance to bind effectively, leading to a significant loss of efficacy and increased potential for contamination of surrounding areas, including water sources.

The timing of rainfall in relation to pesticide application is crucial; immediate precipitation can disrupt the intended pest control measures and diminish the expected longevity of the pesticide’s effectiveness. Understanding this relationship is key for responsible pesticide usage and management, ensuring that applications are timed properly to minimize runoff and environmental contamination.