What factor most influences the risk of pesticide drift during application?

Wind speed is the factor that most significantly influences the risk of pesticide drift during application. When pesticides are applied, whether through aerial spraying or ground equipment, they can become airborne and carried away from the intended target area by wind. Higher wind speeds increase the distance and speed at which pesticide particles can drift, potentially leading to unintended exposure to non-target areas, including nearby crops, waterways, and residential areas.

While temperature and humidity levels can affect the physical properties of the pesticide solution and the evaporation rate, they do not have the same direct impact on the movement of pesticide particles as wind does. Similarly, the type of crop treated may be relevant to which pesticide can be used, but it does not inherently influence the atmospheric conditions at the time of application that lead to drift. Therefore, considering all factors, wind speed stands out as the primary environmental concern when discussing the risk of pesticide drift.