What is commonly the number one factor that influences spray drift?

• A. Droplet size
• B. Wind speed
• C. Pesticide formulation
• D. Temperature

Answer: (A)

Droplet size largely determines how far spray droplets will travel before settling. Smaller droplets are light and highly responsive to air movement, so they can be carried by even light winds and stay aloft longer, increasing drift distance. Larger droplets, being heavier, settle toward the ground more quickly under the influence of gravity, which keeps drift to a minimum. This fundamental relationship means that, under typical spraying conditions, the baseline drift potential is set by how fine or coarse the spray is. Wind, temperature, and formulation can modify that drift, but the size of the droplets is the primary driver. To reduce drift, you’d choose nozzle types and pressures that favor coarser droplets and spray under conditions with lower wind.