|Westra, Phil - COLORADO STATE UNIVERSITY|
|Nissen, Scott - COLORADO STATE UNIVERSITY|
Submitted to: Weed Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 30, 2005
Publication Date: March 28, 2006
Citation: Shaner, D.L., Westra, P., Nissen, S. 2006. Amads increases the efficacy of glyphosate formulations on corn. Weed Technology.Volume 20, PP179-183 Interpretive Summary: Glyphosate is one of the most widely used herbicides in the world and requires adjuvants for maximum activity. This paper determined the effects of AMADS, an acidifying adjuvant, on the efficacy of different formulations of glyphosate on corn. AMADS increased the efficacy of three different glyphosate formulations by three- to four-fold. AMDS was better than ammonium sulfate on overcoming hard water antagonism on glyphosate and increased the rainfastness of the glyphosate formulations. This adjuvant should be useful in reducing the amount of glyphosate needed for effective weed control.
Technical Abstract: Greenhouse studies were conducted to determine the effect of 1-aminomethanamide dihydrogen tetraoxosulfate (AMADS ) at 2% (v/v) as a spray adjuvant on the efficacy of different glyphosate formulations. The formulations tested were the isopropylamine salt (glyphosate-IPA), potassium salt (glyphosate-K) and the acid of glyphosate dissolved in AMADS (glyphosate-A). All formulations were tested at multiple rates with and without AMADS (2% v/v) on greenhouse-grown corn, and growth inhibition was determined by measuring the elongation of the newest emerging leaf between 1 and 7 days after treatment (DAT). AMADS increased the efficacy of all three glyphosate formulations by three- to four-fold. The LD50 for glyphosate-IPA, glyphosate-K and glyphosate-A on corn were 77, 54, and 136 g ae/ha, respectively, without AMADS and 20, 18 and 48 g ae/ha, respectively, with AMADS. AMADS improved the rain fastness of glyphosate-IPA and glyphosate-A when simulated rainfall was applied 1 HAT. In addition, AMADS was better than AMS (2% w/v) in overcoming the antagonism of hard water (200 ppm Ca+2) on glyphosate-K efficacy on corn.