Herbicide Resistance Management

Updated: September 27, 2016

Current Situation

Herbicide resistance is one of the biggest issues faced by U.S. farmers. According to the Weed Science Society of America, without the use of herbicides to control weeds, U.S. soybean and corn farmers would lose half their crop, costing them approximately $43 billion every year. Many farmers now realize that managing existing herbicide-resistant weeds or working to prevent the development of new ones requires complex weed-management strategies. Farmers must implement a diversified weed-management plan that includes using multiple herbicide modes of action and non-chemical controls, like cover crops, tillage and hand weeding, to maintain the effectiveness of chemistries on the market today.  It’s been more than a decade since any new herbicide chemistries were developed — and with no new modes of action under development, it’s not likely to happen soon. New herbicides take 10-15 years to develop, and herbicide chemistries cost about $250 million to bring to market. So maintaining the effectiveness of current products is critical.

Why the Checkoff Cares

Herbicide-resistant weeds cost soybean farmers time and money and impact their profitability.

Key Points

  • The soy checkoff has played a leading role in establishing Take Action, an industry-wide partnership to help farmers manage herbicide resistance.
  • The Take Action industry partnership includes more than 25 universities from major row-crop states around the country, eight major herbicide providers, six farmer-led commodity organizations and one industry organization. 
  • The Take Action effort encourages farmers to adopt weed-management practices that lessen the impact of resistant weeds and preserve current and future herbicide technology.
  • It is important for soybean farmers to better understand weeds on their farm to better manage and prevent the development of herbicide resistance. Knowing when weeds grow and pollinate and how to control them before they go to seed will help give crops the upper hand.
  • Soybean farmers can manage for herbicide-resistant weeds in both no-till and conventional tillage systems through the use of crop rotation, cover crops, tillage and appropriate herbicide applications.
  • University research shows using multiple herbicide sites of action provides better control over weeds.
  • Soybean farmers should be aware of the cost of poor weed control. Managing the risks of herbicide-resistant weeds can help protect the long-term bottom line.
  • In addition to glyphosate resistance, PPO resistance is becoming more widespread – of all of the fields tested in recent research in the southern United States, 20 percent of the weeds were PPO-resistant.

Facts & Figures

  • A soy checkoff-funded survey shows that 45 percent of U.S. soybean farmers use a diversified management plan that includes actions like tillage, burndown or residual herbicides like Authority®, Sencor®, Valor®, Canopy®, Zidua® or others. Eighteen percent of farmers use only a postemergence herbicide program using Glyphosate or Liberty.
  • According to the International Survey of Herbicide Resistant Weeds, 470 resistant weeds have been reported globally. Of these 470, the United States reported 155, more than any other country. Herbicide-resistant weeds have been reported in 86 crops in 66 countries.
  • Weeds have developed resistance to 23 of the 26 known herbicide sites of action and to 160 herbicides, according to the International Survey of Herbicide Resistant Weeds.
  • According to the Weed Science Society of America, without the use of herbicides to control weeds, U.S. soybean and corn farmers would lose half their crop, costing them approximately $43 billion every year.
  • It’s been more than a decade since any new herbicide chemistries were developed — and it’s not likely to happen soon. New herbicides take 10–15 years to develop, and herbicide chemistries cost about $250 million to bring to market.

Other Resources