Drift is the primary cause of phytotoxicity to non-target plants.

• A. True
• B. False
• C. Depends on weather
• D. Only for aerial applications

Answer: (A)

Drift is the primary way pesticides reach plants you didn’t intend to treat, so they end up showing phytotoxic effects. When you apply a spray, especially with fine droplets or high pressure, some of those droplets can be carried by air currents away from the target area. If they land on nearby crops, ornamentals, or wild plants, they can cause leaf burn, stunting, or other injury, even though those plants weren’t part of the treatment plan.

The extent of drift depends on factors you control, like droplet size, nozzle type, spray pressure, application height, and the wind at the time. Smaller droplets and higher pressure tend to drift farther, while heavier, larger droplets stay closer to the target. Weather plays a role by influencing how much drift occurs—wind and temperature inversions can increase the distance droplets travel—but that doesn’t change the basic mechanism. Drift can happen with ground equipment too, not just aerial applications, so it’s the main route of non-target phytotoxicity overall.

So, drift being the main cause makes sense because off-target movement of spray from air currents is the most common way non-target plants are exposed to pesticides.