What factors influence the size of spray droplets?

• A. Pesticide color
• B. Time of day
• C. Wind speed
• D. Nozzle type, orifice size, spray pressure, flow rate, speed of application, and nozzle spacing

Answer: (D)

Droplet size is determined by how the spray system is built and how you run it. The nozzle type and the size of the orifice set the starting diameter of the droplets as they leave the nozzle. The spray pressure adds the energy that breaks the liquid into droplets—higher pressure generally creates smaller droplets, while too much pressure can cause excessive fragmentation or drift. Flow rate matters because the amount of liquid moving through the nozzle interacts with the nozzle design and pressure to shape the droplet spectrum. The speed of application changes how long the droplets are in air and how air flow around the plume affects breakup and evaporation, influencing the final size distribution at the target. Nozzle spacing affects how spray plumes overlap and deposit, which also shapes the overall droplet size distribution seen in the treated area. While wind, temperature, and other environmental factors affect where droplets go and how they behave after leaving the nozzle, they do not set the actual size of the droplets produced by the nozzle system.