What does the term "drift" refer to in aerial application?

The term "drift" in aerial application specifically refers to the unintentional spread of pesticide away from the target area. This phenomenon can occur due to various factors, such as wind speed and direction, temperature, and humidity, all of which can carry the pesticide particles away from the intended application zone. Understanding drift is crucial for minimizing environmental impact and ensuring that the chemical is applied effectively to the target crops or areas without affecting surrounding non-target environments.

The other options relate to different aspects of aerial application but do not describe drift. Mixing pesticides involves ensuring the chemicals are compatible and evenly combined for application, while the application rate refers to the specific quantity of pesticide used per acre. The altitude at which an aircraft operates is concerned with safety and efficiency during flight, rather than the unintended dispersion of applied substances.