To avoid vapor drift, applicators should be most aware of which two factors?

To avoid vapor drift, applicators should be most aware of which two factors?

• A. Wind speed and humidity.
• B. Nozzle size and droplet spectrum.
• C. Application rate and equipment age.
• D. Temperature and pesticide volatility.

Answer: (D)

Vapor drift is the movement of pesticide in its gaseous form away from the application site, carried by air. The two factors that control how much pesticide becomes vapor are how hot it is (ambient temperature) and how readily the chemical turns into vapor (its volatility). When temperatures are high, pesticides with higher volatility vaporize more easily, increasing the chance that vapor drifts off-target. So, the biggest factors to monitor to minimize vapor drift are the current temperature and the pesticide’s volatility. The other factors listed mainly influence the movement of liquid droplets (droplet drift) or other application aspects, not the vapor phase.