Structural Pest Control Applicator Practice Exam

What weather factors help reduce drift during pesticide application?

1. Lack of wind, low temperature and low humidity

2. Lack of wind, low temperatures and high humidity

3. Low wind, high temperatures and high humidity

4. High wind, low temperatures and high humidity

The correct answer is: Lack of wind, low temperatures and high humidity

The selection of lack of wind, low temperatures, and high humidity as factors that help reduce drift during pesticide application is grounded in the understanding of how these weather conditions interact with pesticide behavior. When there is a lack of wind, it minimizes the movement of pesticide droplets away from the target application area. Wind can carry small droplets, leading to drift onto non-target areas, which can cause environmental harm and reduce the effectiveness of the application. Low temperatures can also contribute to reducing drift. At lower temperatures, the volatility of many pesticides is reduced, meaning they are less likely to evaporate and form small airborne particles that are susceptible to being carried off by the wind. Additionally, cooler temperatures can help maintain the physical stability of the pesticide formulation during application. High humidity plays a crucial role as well; it can help keep pesticide particles larger by preventing evaporation, thus promoting better adhesion to the intended surfaces rather than becoming airborne and drifting. High humidity levels reduce the likelihood of small droplets forming due to evaporation, which can also lead to drift. In summary, the combination of a calm wind environment, lower temperatures limiting volatility, and high humidity supporting larger droplet sizes creates optimal conditions for precision in pesticide application and minimizes the risk of drift.