Atrazine.com > Benefits > More Flexible Weed Control Programs

Atrazine can be applied to crops before, during or after planting of the seeds, or even after the crop emerges. It is most often used at low rates in tank mixes or pre-mixes with other, more specialized products, to provide total, season-long weed control (see table). Using atrazine in these mixes offers several benefits:

Combining atrazine with other herbicides enhances control of targeted weeds at minimum application rates. Even as new herbicide active ingredients and new technologies like herbicide-tolerant corn hybrids are introduced, atrazine is increasingly relied upon and promoted for use with other herbicides by universities and herbicide manufacturers. In 1994, 25 percent of broad-spectrum herbicide treatments evaluated in field studies by Corn Belt universities contained atrazine. By 2004, following the introduction of many new corn herbicide active ingredients, 80 percent of broad spectrum herbicide treatments evaluated contained atrazine. Atrazine is not subject to volatile drift from the application site, making it an irreplaceable herbicide option in areas of crop and environmental diversity. Atrazine used in combination or rotation with other products which have different modes of action lowers the risk of weeds developing resistance to those products. For example, weed resistance has developed to 10 ALS inhibitor herbicides used in corn. On average, 65% of each of the acres treated with these herbicides also receives atrazine in tank mix or sequentially, to slow the spread of resistance to the ALS inhibitor herbicidal mode of action. Atrazine is also an effective rotation chemistry to delay the spreading problem of glyphosate herbicide resistance. For particularly invasive weeds (kochia, common cocklebur, smooth pigweed, Palmer pigweed, tall waterhemp, common waterhemp and wild sunflower) already known to be resistant to other herbicides, atrazine is the only product which can be applied either pre- or post-emergence that provides effective control.