Comparison of glyphosate-based herbicides in Nebraska

We compared efficacy of a variety of glyphosate-based products (generic and brand names) on weed control over three years at six Nebraska locations. Weed species included in the study were: velvetleaf, common waterhemp, sunflower, kochia, Russian thistle, lambsquarters and a mix of foxtails. Depending on the year or location, we tested the following glyphosate-based products at two rates (label rate and half-rate): Roundup Ultra, Roundup UltraDRY, Roundup UltraMAX, Roundup WeatherMAX, Touchdown w/IQ, Cornerstone, Clearout 41 Plus, GlyphoMAX, Glyfos Xtra, and Glyphomax Plus.

All herbicides provided excellent weed control (> 90%) regardless of the rate or brand name. For example, there was no significant difference in the level of weed control for a brand name Roundup™ Ultra Dry when compared to the generic product such is Clearout41™ Plus. Similarly, the level of weed control was not significantly different for a brand name product such as Roundup WeatherMax and a generic product , Clearout41 Plus, or any other herbicide tested.

These findings were similar to results reported by colleagues in other states. Generic glyphosate-based products can provide a valuable tool for weed control in glyphosate-tolerant crops, especially for those producers interested in lowering crop production inputs by reducing weed control costs. Producers may want to place less emphasis on brand selection and more emphasis on using the appropriate herbicide rate for the weeds present and observing environmental factors.

In addition, with the growing popularity of relatively inexpensive generic glyphosate-based products, there is an even greater need for their proper use. Their value can be preserved only by proper management and reduced overuse. This becomes even more important when other Roundup Ready crops become more readily available (e.g. Roundup Ready corn and Roundup Ready alfalfa). It is easy to fall into a trap of overusing glyphosate when one glyphosate-resistant crop is grown after another. Proper use of glyphosate-based technology, as a component of an integrated weed management program, is the key to preserving the long-term benefits of this technology while avoiding many of the concerns about its use, or misuse.