Contact:  Dr. Andrew Hewitt, Special Projects Director, Stewart Agricultural Research Services, 1893 Highway K, Clarence, MO 63437 email: ahewitt@marktwain.net

 Summary: Future pesticide labels will require increasing knowledge of droplet size spectra.  Models are available, such as those of the USDA-ARS and SDTF, that can estimate emission droplet size spectra for most of the major aerial nozzle types with basic reference tank mixes; however, actual emission droplet size spectra may vary from the model estimates due to tank mixing and actual nozzle position (on the boom)/ use conditions.  Therefore, applicators are encouraged to measure droplet size performance in the field for their precise aircraft setup and tank mixes.  It is well known that wind tunnel and field droplet sizing differ with respect to sampling, resolution, collection efficiency, evaporation effects and other differences.  Understanding these relationships is essential to the optimal application of the findings of both systems.  A study was conducted to compare the two approaches to droplet sizing.  The present paper explains how pesticide labeling will reference droplet size spectra, and explains the wind tunnel atomization part of the study. 

<Select to See the Presentation>

<Select to View the Manuscript>