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Title: EFFECT OF DIFFERENT NOZZLE TYPES ON DRIFT AND EFFICACY OF ROUNDUP ULTRA

Author
item JONES, E - DREC
item Hanks, James
item WILLS, G - DREC

Submitted to: Mississippi Agricultural and Forestry Experiment Station Technical Bulletin
Publication Type: Experiment Station
Publication Acceptance Date: 2/20/2002
Publication Date: 3/14/2002
Citation: Jones, E.J., Hanks, J.E., Wills, G.D. 2002. Effect of different nozzle types on drift and efficacy of roundup ultra. Mississippi Agricultural and Forestry Experiment Station Technical Bulletin. MAFES Bulletin #1119.

Interpretive Summary: Field and laboratory studies were conducted to evaluate four commonly used conventional hydraulic nozzles and an air-induction type nozzle to determine the effect on spray droplet size, spray patterns, and efficacy when applying Roundup Ultra. When Roundup Ultra was applied with the different nozzles at the rate of 1 lb a.i.in 10 gallons of water per acre, the percent volume of fine, highly driftable spray drolets (<105 microns in diameter) varied from 2 to 53% and the volume median diameter of droplet sizes varied from 99 to 632 microns. Spray patterns were different among nozzle types, but weed control in the field treatments was similar (91 to 100%) with all five types of spray nozzles for each of three weedy species: nodding spurge, pitted morningglory, and southwestern cupgrass. Results of this study indicate that air-induction nozzles produce larger, less driftable spray droplets and smaller amounts of fine driftable spray droplets than the nozzle types most commonly used at this time without affecting the efficacy of the herbicide.

Technical Abstract: Both field and laboratory experiments were conducted to determine the effect of five types of spray nozzles at spray pressures from 20 to 70 pounds per square inch (psi) on spray droplet size, spray patterns, and efficacy of Roundup Ultra herbicide. When Roundup Ultra was applied with the different nozzles at the rate of 1 lb a.i. in 10 gallons of water per acre, the percent volume of fine, highly driftable spray droplets (<105 microns in diameter) varied from 2%, with the air-induction nozzle, to 53% and the volume median diameter of droplet sizes varied from 99 to 632 microns. The widths of the spray patterns with the various types of spray nozzles ranged from 20 to 50 inches. Weed control in the field treatments was similar (91 to 100%) with all five types of spray nozzles for each of three weedy species: nodding spurge, pitted morningglory, and southwestern cupgrass. Results of this study indicate that air-induction nozzles produce larger, less driftable, spray droplets and smaller amounts of fine driftable spray droplets than the nozzle types most commonly used at this time without affecting the efficacy of the herbicide.