Monsanto, Syngenta, Dow and others are battling it out over which glyphosate product to use. Is there really a difference in product performance? Last year I conducted a test on different brands of glyphosate products at the Hundley-Whaley Farm on Roundup Ready beans. Roundup UltraMax, Glyphomax Plus, Touchdown IQ and GlyStar Plus were compared. Each product was used in accordance with label instructions and each product performed equally well, and there were no apparent differences in crop injury.
Bob Hartzler, Weed Scientist at Iowa State University, wrote on glyphosate formulations in January of 2001 www.weeds.iastate.edu/mgmt/2001/glyphosateformulations.htm He stated, "In summary, the major differences affecting the performance of glyphosate products are the surfactants included in the package rather than the salt formulated with the product. As with different amine salts of 2,4-D, we do not expect significant differences in performance of different salts of glyphosate. We also do not expect consistent differences among products when used at equivalent rates and label recommendations for additives are followed."
Jim Kells and Chad Lee, Weed Scientists at Michigan State University, recently wrote on trials run in their state last year www.msue.msu.edu/ipm/CAT01_fld/FC02-08-02.htm#3 They summarized the work by stating that all glyphosate formulations should effectively control weeds if the weeds were treated at the stage recommended on the herbicide label; if rate of glyphosate on the label were followed; if ammonium sulfate were used at the rate of 17 pounds per 100 gallon of spray solution; and if surfactants were used as recommended on the label.
What is the bottom line? I believe that nearly all of the research results from independent researchers would suggest that producers have a lot of options when it comes to selecting and using glyphosate products. If price is the only factor you look at, price the products and apply the one that costs the least amount of money. Be sure to figure in all additives recommended on the label when you do this. However, if company support of the product is important you may want to work with your dealer to determine which company and product he/she suggest you use.