Proper selection of adjuvants is essential for effective weed control with herbicides. Unlike herbicides, adjuvants are not regulated - thus anything can be marketed for this purpose and manufacturers are not required to describe the active ingredients. This leads to the introduction of questionable products making unrealistic claims. The newest ruse is the promotion of products with the supposed ability to overcome glyphosate resistance. While there are many glyphosate resistance mechanisms in weeds (e.g. overexpression of the target site, insensitive target site, altered translocation), there are no known cases where resistance is due to reduced absorption of the herbicide. Thus, spray adjuvants will not be able overcome herbicide resistance since adjuvants only aid herbicides in penetrating the leaf cuticle. Weed scientists at Purdue University recently published results of a study evaluating two adjuvants marketed for managing glyphosate resistant weeds. As expected, there were no simple fixes. Managing herbicide resistance requires diversification of the weed management program, not the addition of miracle products. NanoTechnology Adjuvants- Newsletter.pdf
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- Retired Weed Scientist and Professor of Agronomy