Which term best describes drift of vapor-form pesticides that may escape the application site?

• A. Vapor Drift (Volatility)
• B. Particle Drift
• C. Runoff
• D. Leaching

Answer: (A)

The key idea here is how a pesticide moves when it changes to a vapor and travels with the air. Vapor drift describes the movement of the pesticide in its vapor form away from the application site because of the pesticide’s volatility. Some chemicals readily vaporize, especially at higher temperatures or with certain formulations, so they can drift through the air even after spray droplets have settled. This is different from particle drift, which is the physical movement of spray droplets; runoff, which is water moving pesticide off the surface; and leaching, which is movement down through the soil with water.

So, vapor drift (volatility) is the correct term because it specifically describes pesticide movement in the vapor phase caused by volatility, separating it from drift of droplets, surface wash-off, or soil movement.