Minnesota Pesticide Applicator Practice Test

Which conditions can influence pesticide vapor drift?

1. Temperature and wind speed

2. Humidity and soil type

3. Time of day and color of spray

4. Distance to water sources

The correct answer is: Temperature and wind speed

The influence of temperature and wind speed on pesticide vapor drift is significant because both factors directly affect how pesticides behave once they are applied. Higher temperatures can increase the volatility of certain pesticides, allowing them to evaporate more quickly and potentially drift further from the application site. When the temperature rises, the molecules of the pesticide become more energetic and can transition into vapor form more readily. Wind speed plays a crucial role in determining how far and in what direction the pesticide drift will occur. Stronger winds can carry pesticide vapors away from the target area more rapidly, increasing the likelihood of off-target movement that could impact neighboring crops, non-target organisms, or even urban areas. In contrast, while humidity can influence pesticide efficacy, soil type does not directly affect vapor drift, and factors such as the time of day, color of spray, and distance to water sources have lesser roles in influencing the behavior of pesticide vapors in the air. Therefore, understanding the interplay between temperature and wind is critical for applicators to minimize the risks associated with vapor drift.