What is Acetochlor?

Acetochlor is an herbicide that is widely used in Minnesota to control weeds in corn, soybean, and sugar beet acres. The MDA has frequently detected acetochlor in streams and other surface waters in Minnesota, occasionally at concentrations above or nearing state water quality standards. The following sections under "Learn More" further describe acetochlor's role in Minnesota agriculture, its impact on Minnesota's environment, and actions being taken to reduce the presence of acetochlor in water.


Pesticide Type Herbicide (Group 15)
Chemical Class Chloroacetamide herbicide
Common Trade Names* Harness, Surpass, Confidence, Keystone, Resicore, SureStart, TripleFlex, Volley, and Warrant
Registration Status EPA: Registered on corn since 1994
MN: Currently registered for corn, soybeans, sugarbeets, alfalfa, and sorghum

Chemical structure diagram of acetochlor

*No endorsement is implied in the referencing of trade names.

Current activities and updates

  • 2023: Response to acetochlor water quality impairment in Silver Creek
    A response plan to the Silver Creek impairment is being developed in collaboration with the Minnesota Pollution Control Agency. The MDA is collaborating with local partners to address the acetochlor contamination in Silver Creek. Silver Creek is the only water body impaired for acetochlor in Minnesota at this time.
  • 2018: Revisions to Acetochlor Water Quality Best Management Practices (BMPs)
    The BMPs were revised to protect Minnesota's groundwater and surface water from potential herbicide contamination resulting from normal agricultural use. These voluntary BMPs should be adopted when applying acetochlor in Minnesota. Water Quality Best Management Practices for Acetochlor (PDF)

  • 2016: Silver Creek impairment
    Silver Creek was added to the Environmental Protection Agency’s impaired waters list after the acetochlor concentration was detected above the state chronic water quality standard. Silver Creek is a tributary to Bevens Creek, which is located at the western edge of the Twin Cities Metropolitan Area in Carver and Sibley counties.

  • 2013: Response to acetochlor water quality impairments
    Two south-central Minnesota streams, the Le Sueur River and Little Beauford Ditch, were on the state's list of impaired waters because of in-stream concentrations of acetochlor. A response to the impairments was developed and implemented which resulted in their delisting in 2014. Additional information on the response plan and the implemented activities can be found in the Le Sueur River and Little Beauford Ditch Acetochlor Impairment Response Report (PDF)