Increase Your Crops Competitive Advantage Against Weeds

Increase Your Crops Competitive Advantage Against Weeds

By Nora Schultz, Sales Agronomist, CCA

During this prepay season, take the time to examine your herbicide program and explore if there are any ways to increase your crops competitive advantage against weeds. Herbicide resistance is one of the largest issues facing agriculture today. Although we seem to focus on one or two weeds most often, many species throughout the country have developed resistance to a variety of our herbicide options. Multiple species have also become resistant to more than one chemical compound. Accepting this reality and looking toward long-term herbicide-resistance strategies are important steps in slowing the progress of resistant biotypes. Using tank mixes (more than one mode of action at a time) and using overlapping residuals are great long term strategies to start with.


  • It is crucial to begin the season with a residual pre-plant or pre-emergence application to reduce the number of weeds that need to be controlled with a post-application. This will then reduce the pressure on some of our post emergence herbicides like glyphosate.
  • Controls early weeds that would otherwise compete with the crop as it becomes established.
  • Use of another residual herbicide with a post application extends the control over weeds with a large emergence window.


  • Herbicides control weeds in a variety of ways and are classified into groups by their site of action. By using multiple products that work in different ways, plants are less likely to survive the application and develop resistance.
  • Follow labeled instructions for rates, water requirements, surfactants, and environmental conditions to get the most out of each application
  • Each chemical label will also list suitable tank mix partners.
  • Common tank mix partners for post-emergence come from Group 27 and are classified as pigment inhibitors, specifically HPPD inhibitors. This groups controls broadleaves and is another residual in corn. HPPD’s also provide another residual piece to the weed management puzzle. 
  • Group 14 herbicides, commonly called ‘burners’, are cell membrane disrupters. These are PPO inhibitors that are often partnered in soybean post-emergence application for broadleaf control.
  • Look on the front page of herbicide label for a listing of site of action group or groups. 


  • For those of you that know a weed resistance issue exists in your field, switching your crops herbicide tolerances is an easy way to begin.
  • Talk to your Jacobsen Seed Dealer about our options in Round Up and Liberty Link corn and also explore if Liberty Link or Round Up Ready 2 Xtend soybeans can help get you the control you need.