Why do aerial applicators often choose to apply agrochemicals at dawn or dusk?

Aerial applicators often choose to apply agrochemicals at dawn or dusk primarily to reduce evaporation rates and minimize drift. During these times, the cooler temperatures and higher humidity levels are more favorable for effective application. At dawn or dusk, evaporation rates are lower compared to the heat of midday, which means that the agrochemicals remain in liquid form for longer periods, increasing their efficacy on the target area.

Furthermore, applying these chemicals during times when wind speeds are typically lower also helps to minimize drift. The combination of lower temperatures and reduced wind leads to a more controlled application, ensuring that the agrochemicals land where they are intended and limiting exposure to non-target areas, which is crucial for environmental safety and effective pest or weed control.

While other factors like visibility, the flying experience, and avoiding high temperatures are also considerations for aerial applicators, the primary and most critical reason for choosing these times is centered around optimizing the application conditions to safeguard both efficacy and environmental impact.