In pesticide applications, which factor most directly influences drift potential?

• A. Wind speed.
• B. Temperature.
• C. Humidity.
• D. Soil moisture.

Answer: (A)

Drift potential is driven by how air moves the spray after it leaves the nozzle. Wind speed directly controls how far and how fast droplets are carried off target; the stronger the wind, the more droplets can travel beyond the intended area. This makes wind speed the factor most directly linked to drift potential. Temperature, humidity, and soil moisture can affect evaporation and where droplets finally deposit, but they don’t determine how far the spray can be carried through the air as wind does. Humidity and temperature influence droplet size and evaporation somewhat, but their effect on drift distance is secondary to the impact of wind speed, and soil moisture relates more to surface conditions than to airborne movement.