Which two factors are most important to avoid spray drift?

Which two factors are most important to avoid spray drift?

• A. Temperature and humidity
• B. Pesticide formulation type and color
• C. Droplet size and wind direction/speed
• D. Time of day

Answer: (C)

Minimizing spray drift hinges on two practical controls: how big the droplets are when they leave the nozzle, and what the air is doing as they travel. Droplet size matters because heavier, larger droplets fall to the ground more quickly and are less carried off-target by air currents. In contrast, very fine droplets stay suspended longer and can be carried far by even light winds. Wind direction and speed are equally critical because they determine the plume’s path; even with larger droplets, a gusty or misdirected wind can push spray onto non-target areas.

So, using a coarser droplet size and spraying under calm or favorable wind conditions reduces the chance that spray drifts away from the intended target. Temperature, humidity, formulation nuances, and time of day can influence other aspects of application, but they don’t affect drift as directly or as strongly as droplet size and wind.