Novel Lipophilic Surfactant Adjuvants for Spray-Drift Reduction

There are several types of drift-reduction technology (DRT) adjuvants commercially available. Natural and synthetic water-soluble polymers function by increasing extensional or shear viscosity. These polymers do a very good job reducing fines, but they can significantly increase volume median diameter (VMD) and broaden the particle-size distribution (PSD). Oil-based products produce emulsions that function to keep small spray drops from forming during the atomization process. A novel DRT adjuvant chemistry has been discovered that reduces fines without increasing VMD or broadening PSD significantly. This novel chemistry is lipophilic surfactants. These surfactants were tank mixed with a glyphosate dilution and their spray PSD was measured using a Sympatec HELOS/KF laser diffraction particle-size analyzer. The experimental procedure followed ASTM Standard Test Method E2798-11 [“Characterization of Performance of Spray Drift Reduction Adjuvants for Ground Application,” Annual Book of ASTM Standards, Vol. 11.05, ASTM International, West Conshohocken, PA, 2011]. The standard uses measurements of particle-size distribution generated when the spray-tank mixture includes the pesticide formulation. The lipophilic surfactant used in this study was an alcohol alkoxylate. This surfactant significantly reduced fines by 40 % to 50 %, and it narrowed the particle-size distribution.