BETTER KILL. The right adjuvant makes a difference in weed control, as this side-by-side, same-field comparison shows. The weeds on the left were treated with Sonic herbicide and a conventional MSO adjuvant. Those on the right were treated with Sonic and a crop oil concentrate. Photo Courtesy United Suppliers

Adjuvants in herbicides have been an important part of the mix for no-tillers since the first household detergent was added to a tank of Roundup somewhere in distant history.

Adjuvant use has become much more scientific and precise over the years. But researchers say the cost of crop-protection chemistry, the battle with herbicide-resistant weeds, and the need to maximize yields will make the proper use of adjuvants even more important to farmers in years to come.

More Complex

Making sure herbicides effectively arrive at their intended destination is a top priority, and to do that, the crop protectant industry is trending toward the use of more combinations of different adjuvants, as opposed to a simple surfactant and ammonium sulfate (AMS) addition to the tankmix, says Patrick McMullan, adjuvant development manager at United Suppliers in Ames, Iowa.

Because of the need to maximize efficacy of crop protectants due to the use of additional herbicides with glyphosate, McMullan says more no-till farmers using glyphosate-based programs are increasing their use of oil-based adjuvants such as Methylated Seed Oils (MSO) and petroleum-based crop oil concentrates (COC).

Rich Zollinger, Extension weed specialist at North Dakota State University, says while growers are shifting to more complex adjuvant…