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ARS Home » Research » Publications at this Location » Publication #183079
Title: INFLUENCE OF DRIFT CONTROL ADJUVANTS ON APPLICATIONS OF GLYPHOSATE

Author
item WILLS, GENE - MAFES
item Hanks, James
item JONES, ELIZABETH - MAFES
item MACK, ROBERT - MAFES
item UNDERWOOD, ALLEN - HELENA CHEMICAL

Submitted to: International Symposium on Adjuvants for Agrochemicals
Publication Type: Proceedings
Publication Acceptance Date: 10/15/2004
Publication Date: 11/12/2004
Citation: Wills, G.D., Hanks, J.E., Jones, E.J., Mack, R.E., Underwood, A.K. 2004. Influence of drift control adjuvants on applications of glyphosate. International Symposium on Adjuvants for Agrochemicals. Cape Town, South Africa. Pg 143-148.

Interpretive Summary: Field and laboratory studies were conducted at Stoneville, MS to investigate the effect of four polymer-based experimental drift reducing adjuvants combined with glyphosate herbicide formulations with (Roundup UltraMax®) and without surfactant (Rodeo®) on droplet size, spray patterns, and efficacy of the spray mixtures. Field applications were to plots 12 m long, 4 m wide and interspaced with barnyardgrass, pitted morningglory, velvetleaf, and prickly sida. Efficacy was determined by visual ratings whereby 0 = no control and 100% = complete kill of shoots. Spray patterns were determined by applying 600 ml of glyphosate at 0.45 kg in 94 L of water plus each drift reducing adjuvant to a patternator. This device consisted of a sheet of corrugated metal with troughs spaced 6 cm apart and slanted to empty into 100-ml graduated cylinders. Droplet size was measured using a Malvern laser analyzer. At 2 weeks after treatment, percent control of four weedy plant species with both glyphosate formulations was reduced, not affected, or increased by the addition of these drift control adjuvants. Spray patterns were not appreciably altered by the addition of the drift control adjuvants. The volume of highly driftable spray droplets (<144 microns diameter) of glyphosate herbicide was 58 and 56% for glyphosate with no drift control adjuvant both with and without surfactant, respectively, and was variously reduced from 5 to 41 percentage points by the addition of four drift control adjuvants.

Technical Abstract: The volume of fine, highly driftable spray droplets (<144 microns diameter) of glyphosate herbicide (0.45 kg/ai in 94 L of water/ha and 276 kPa pressure) was 58 and 56% for glyphosate with no drift control adjuvant both with and without surfactant, respectively, and was variously reduced from 5 to 41 percentage points by the addition of four drift control adjuvants. At 2 weeks after treatment, percent control of four weedy plant species with glyphosate both with and without surfactant was either reduced, not affected, or increased by the addition of these drift control adjuvants. Spray patterns were not appreciably altered by the addition of the drift control adjuvants.