Submitted to: Ohio State University Extension Publication
Publication Type: Other
Publication Acceptance Date: 2/24/1998
Publication Date: N/A
Citation: Interpretive Summary: Spray drift is becoming an increasing important factor for pesticide applicators to consider and it is considered to be one of the most challenging problems facing applicators and pesticide manufacturers. Equipment manufacturers are responding to these concerns and introducing different methods for reducing drift including drift reduction nozzles. The new equipment is designed to produce fewer drift prone droplets. Laser droplet sizing equipment and wind tunnel tests demonstrated the drift potential of standard and new drift reduction nozzles. The drift reduction nozzles performed differently from each other but these new nozzles did produce fewer downwind deposits and fewer drift prone droplets than standard nozzles. The traditional method of reducing spray drift, by reducing nozzle pressure and using larger orifices, was also shown to significantly reduce downwind drift. This research is part of an on-going effort aimed at minimizing spray drift. The results of this research will help growers make more informed decisions when selecting equipment to provide the safest and most efficient method of pesticide application.
Technical Abstract: Spray drift is becoming an increasingly important factor for pesticide applicators to consider and it is considered to be one of the most challenging problems facing applicators and pesticide manufacturers. Computer simulations have shown that drift is less likely to be a problem when spraying with droplets 200 microns and larger in size. Equipment manufacturers are responding to these concerns and introducing different methods for reducing drift including drift reduction nozzles. USDA-ARS and Ohio State University engineers conducted tests to determine the effectiveness of two of the new drift reduction nozzles in reducing drift. Laser droplet sizing equipment was used to characterize the droplet size distributions produced by these nozzles. Wind tunnel experiments were conducted to evaluate downwind spray deposits in a 10 mph wind. The new drift reduction nozzles produced much fewer drift-prone droplets. They also produced fewer downwind ground and airborne deposits than standard nozzles. The different drift reduction nozzles provided different levels of drift minimization. However, reducing nozzle pressure and using larger orifices was shown to also significantly reduce downwind drift potential. Disrupting the normal operating condition of one of the nozzles by plugging an air intake hole did not appear to significantly change the performance of the nozzle. It would appear that contamination likely to result from operating in dusty conditions would not interfere with the performance of this particular nozzle and would not result in more spray drift.