Which pesticide formulation often clogs nozzles and screens?

• A. Ultra low volume
• B. Soluble powders
• C. Wettable powders
• D. Emulsifiable concentrates

Answer: (C)

Finely divided solid particles in some pesticide forms can clog spray equipment. Wettable powders are dry powders that must be dispersed in water to form a suspension, and their very fine particles can be dusty. If the mixture isn’t kept well agitated or if fines settle and cling to screens, they can plug nozzle screens and reduce flow, causing uneven spray and clogs. This makes wettable powders a common culprit for nozzle and screen blockages.

Other formulations behave differently: emulsifiable concentrates are liquids that emulsify in water and typically pass through nozzles as liquid droplets, though they can leave films if misused. Ultra low volume products are designed for very small spray volumes and are formulated to minimize solids; soluble powders dissolve completely in water, leaving no solids to clog filters or nozzles.