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Rotating sites of action to manage resistance​

Luke Peters

By Luke Peters,

corn herbicides product manager

Dow AgroSciences



Herbicide resistance continues to be top of mind for Midwest growers. It’s important now more than ever to rotate multiple sites of action in weed control programs to manage it.


Although sites of action and modes of action are sometimes used interchangeably, there is a difference between them. The site of action refers to the location within the plant where it is effected by the herbicide, while the mode of action describes how the herbicide controls 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, be sure to incorporate multiple sites of action into a weed control program each year.


Find a full list of sites of action, modes of action, active ingredients and trade names 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. SureStart and SureStart II are not registered for sale or use in all states. SureStart and SureStart II 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. Always read and follow label directions. ©2015 Dow AgroSciences LLC   M53-917-011 (10/15) BR   DAAGSSRT5054


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