Indiana Pesticide Applicator Core Practice Exam

Which of the following describes the movement of pesticides in vapor form?

1. Runoff

2. Spray drift

3. Vapor drift

4. Leaching

The correct answer is: Vapor drift

The movement of pesticides in vapor form is correctly described as vapor drift. This term specifically refers to the process by which pesticide vapors can move away from the initial application site due to environmental conditions such as temperature and wind. When pesticides are applied, they can volatilize into the air; if conditions are right, these vapors can travel significant distances from where they were originally sprayed. Vapor drift is particularly important to understand because it can lead to unintended exposure of human populations, wildlife, and non-target plants, even when the pesticides are not physically present in liquid form on the surface. Other forms of movement, such as runoff, involves liquid pesticides moving over the surface of the ground, typically after rainfall or irrigation. Spray drift refers to the airborne particles that are carried away during the application process, particularly with spray methods, and is also not limited to vapor. Leaching describes the process of pesticides moving downward through the soil profile into groundwater, which is relevant for liquid formulations but not for vapor movement. Understanding these distinctions helps ensure the safe and effective use of pesticides while minimizing off-target effects.