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ARS Home » Research » Publications at this Location » Publication #144487
Title: SPRAY DROPLET COMPARISONS FOR GLYPHOSATE FORMULATIONS

Author
item Hanks, James
item WILLS, GENE - MAFES-DREC
item JONES, E - MAFES-DREC
item MILLS, J - MONSANTO

Submitted to: Proceedings of Southern Weed Science Society
Publication Type: Proceedings
Publication Acceptance Date: 1/20/2003
Publication Date: 1/20/2003
Citation: Hanks, J.E., Wills, G.D., Jones, E.J., Mills, J.A. 2003. Spray droplet comparisons for glyphosate formulations. Proceedings of Southern Weed Science Society. 2003. Vol. 56:316.

Interpretive Summary:

Technical Abstract: Preliminary studies were conducted to evaluate the effects of three glyphosate formulations on spray droplet size. A Malvern laser droplet analyzer was used to determine spray droplet size for three glyphosate formulations; Roundup Original®, UltraMax®, and WeatherMax®. Each glyphosate formulation contains surfactant, but additional surfactant is recommended with Roundup Original®. Two surfactants, SurfAid® and Activate Plus® were evaluated with Roundup Original® at the recommended rate of 0.5% (v/v). Spray solutions were mixed to provide 0.8 kg a.e./ha (0.75 lb a.e./A) in a 94 l/ha (10 gpa) spray volume. All evaluations were conducted using a Spraying Systems Turbo TeeJet® 11003vp nozzle. Volume median diameter and the percentage of spray volume in droplets less than 144 microns were determined with the Malvern, at a range of pressures from 138 to 550 kPa (20-60 psi). Volume median diameter was slightly smaller for all glyphosate formulations compared to water, but there were no significant difference among glyphosate formulations. The percent spray volume in droplets less than 144 microns ranged from 5% to 27% and volume median diameter ranged from 244 to 474 microns over the range of pressures. The addition of Activate Plus® slightly decreased the percent of spray volume in droplets less than 144 microns, whereas the addition of SurfAid® caused a slight increase.