N-phosphonomethylglycine (glyphosate) is firmly established as the preeminent herbicide of choice in a wide range of applications for the crop protection industry. It is well known that the efficacy of glyphosate can be enhanced with the use of surfactant adjuvants. Surfactants based on amine chemistry seem to work especially well, and an adjuvant that has found widespread use in glyphosate is the tallowamine ethoxylate. While tallowamine ethoxylates provide excellent efficacy, they also have several limitations. They raise irritancy concerns and limit the maximum loading of glyphosate in the formulation concentrate.
It has been found recently that ethylenediamine alkoxylates can be used as effective adjuvants in glyphosate formulations. Specifically, they can be used in blended adjuvants for several functions. They allow a higher glyphosate loading over that provided by tallowamine ethoxylates alone. They also reduce the toxicity profile of the glyphosate formulation significantly. Ethylenediamine alkoxylates have passed EPA inert reassessment and are listed on the new 40CFR 180.960 “Polymers; Exemptions from the Requirement of a Tolerance.” This paper will discuss the utility of this new class of glyphosate surfactants.