Manage Herbicide Resistance Through Multiple Sites of Action

With more weeds continuing to become herbicide-resistant, it’s important now, more than ever, to ensure that your customers are rotating multiple sites of action in their weed control program to manage resistance.

Although sites of action and modes of action are terms that have been used interchangeably, there is a difference between the two. The site of action refers to the location within the plant where it is affected by the herbicide, while the mode of action describes how the herbicide is controlling the weed.

SureStart® II herbicide contains three nonglyphosate modes of action to control tough weeds, including waterhemp, marestail and giant ragweed.

Here are the three active ingredients in SureStart II, along with the correlating sites and modes of action:

  1. Acetochlor:
    • Site of action: long-chain fatty acid inhibitor (Group 15)
    • Mode of action: seedling shoot growth inhibitor
  2. Clopyralid:
    • Site of action: specific site unknown (Group 4)
    • Mode of action: growth regulator (synthetic auxins)
  3. Flumetsulam:
    • Site of action: ALS inhibitor (Group 2)
    • Mode of action: amino acid synthesis inhibitor

As weed resistance continues to spread across the Corn Belt, remind your customers about the importance of incorporating multiple sites of action into their weed control programs each year.

A full list of sites of action, modes of action, active ingredients and trade names can be found in the Corn and Soybean Herbicide Chart produced by the University of Wisconsin-Extension.

For more information on SureStart II, visit or contact your Dow AgroSciences sales representative.

®Trademark of The Dow Chemical Company (“Dow”) or an affiliated company of Dow. FulTime NXT, Keystone LA NXT and Keystone NXT are federally Restricted Use Pesticides. Duramax, Durango DMA, FulTime NXT, Keystone LA NXT, Keystone NXT, Instinct II, Sonic, SureStart II, Surpass NXT and Surveil Co-pack are not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. FulTime NXT, Keystone LA NXT, Keystone NXT, SureStart II and Surpass NXT are not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Do not fall-apply anhydrous ammonia south of Highway 16 in the state of Illinois. Regulatory approvals are pending for Enlist cotton. Always read and follow label directions. ©2014 Dow AgroSciences LLC