Cumulative Map of Herbicide Resistant Weeds In Michigan

In 1980, common lambsquarters was the first weed to be confirmed resistant to the triazine herbicides (Group 5) in Huron County, Michigan by Ph.D. student E. Patrick Fuerst and Professor Donald Penner. Over the years following a few more weeds were confirmed resistant by MSU weed scientists Donald Penner, Jim Kells, Karen Renner, and Bernard Zandstra. In 2000, Steve Gower began a more formalized screening program through MSU Diagnostic Services. In 2010 the screenings were moved to the laboratory of Christy Sprague and in 2015 they returned to Diagnostic Services under the direction of Erin Hill. The current screening process, supported largely by the Michigan Soybean Promotion Committee, involves greenhouse bioassays started from weed seeds harvested from escaped weeds. Each weed is screened against five to six different sites of action in an effort to detect new incidents of resistance and cases of multiple resistance.





Herbicide Resistance Encountered In Macomb, MI Herbicide Resistance Encountered In Isabella County Herbicide Resistance Encountered in Shiawassee County Herbicide Resistance Encountered In MIchigan Herbicide Resistance Encountered in Ingham County Herbicide Resistance Encountered In Oakland, MI Herbicide Resistance Encountered in St. Clair County, MI Herbicide Resistance Encountered In Washtenaw County, MI Herbicide Resistance Encountered in Lenawee County, MI Herbicide Resistance Encountered in Monroe County, MI Herbicide Resistance Encountered In Hillsdale County, MI Herbicide Resistance Encountered in Branch County, MI Herbicide Resistance Encountered In St. Joseph County, MI Herbicide Resistance Encountered in Cass County, MI Herbicide Resistance Encountered in Berrien County, MI Herbicide Resistance Encountered In Allegan County, MI Herbicide Resistance Encountered In Barry County, MI Herbicide Resistance Encountered In Newaygo County, MI Herbicide Resistance Encountered in Missauki County, MI Herbicide Resistance Encountered In Ionia County, MI Herbicide Resistance Encountered In Montcalm County, MI Herbicide Resistance Encountered In Mason County, MI Herbicide Resistance Encountered in Oceana County, MI Herbicide Resistance Encountered In Tuscola County, MI Herbicide Resistance Encountered in Huron County, Mi Herbicide Resistance Encountered In Lapeer County, MI Resistance Encountered In Saginaw County, MI Herbicide resistance encountered in Leelanau County, MI Herbicide Resistance Encountered in Grand Traverse County, MI Herbicide Resistance Encountered in Benzie County, MI Herbicide Resistance Encountered in Wexford County, MI Herbicide Resistance Encountered in Wayne County, MI Herbicide Resistance Encountered in Manistee County, MI Herbicide Resistance Encountered in Claire County, MI Herbicide Resistance Encounted in Bay County, MI Herbicide Resistance Encountered in Antrim County, MI Herbicide Resistance Encountered in Newaygo County, MI Herbicide Resistance Encountered in Ottawa County, MI Herbicide Resistance Encountered in Eaton County, MI Herbicide Resistance Encountered in Van Buren County, MI Herbicide Resistance Encountered in Delta County, MI Herbicide Resistance Encountered in Montmorency County, MI Herbicide Resistance Encountered in Presque Isle County, MI Herbicide Resistance Encountered in Calhoun County, MI

Click on shaded counties to view confirmed cases of herbicide-resistant weeds; the number of resistant species per county is noted. Counties showing no resistance may still have resistant weeds, as samples have not been submitted for all counties. *Map updated April 2018, listing updated April 2018*.


Allegan Co. (back to map)

  • Common ragweed
    • ALS resistant (2015)
  • Common purslane
    • Triazine resistant (2015)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2016)
    • Glyphosate resistant (2017)
    • Triazine resistant (1990s)
  • Palmer amaranth
    • Multiple resistant- ALS & triazine (2015)
    • ALS resistant (2015)


Antrim Co. (back to map)

  • Common ragweed
    • Multiple resistant- ALS & glyphosate (2016)
  • Horseweed (marestail)
    • Glyphosate resistant (2016)


Arenac Co. (back to map)

  • Common ragweed
    • ALS resistant (2015)


Barry Co. (back to map)

  • Palmer amaranth
    • Multiple resistant- ALS, glyphosate, & triazine (2014)
    • Multiple resistant- ALS & glyphosate (2012)
  • Velvetleaf
    • Triazine resistant (2002)


Bay Co. (back to map)

  • Wild carrot
    • Synthetic auxin resistant (1993)


Benzie Co. (back to map)

  • Horseweed (marestail)
    • Glyphosate resistant (2016)
  • Redroot pigweed
    • ALS resistant (2016)


Berrien Co. (back to map)

  • Common ragweed
    •  Glyphosate resistant (2017)
  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2014)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2014)

Branch Co. (back to map)

  • Common lambsquarters
    • ALS resistant (2014)
  • Common ragweed
    • ALS resistant (2014)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2015)


Calhoun Co. (back to map)

  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2017)

Cass Co. (back to map)

  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2014)
    • Glyphosate resistant (2017)


Clare Co. (back to map)

  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2016)

Clinton Co. (back to map)

  • Common waterhemp
    • ALS resistant (2015)
  • Horseweed (marestail)
    • Glyphosate resistant (2011)
  • Palmer amaranth
    • Multiple resistant- ALS & glyphosate (2012)
  • Prostrate pigweed
    • Uracil resistant (2012)


Delta Co. (back to map)

  • Horseweed (marestail)
    • ALS resistant (2017)

Eaton Co. (back to map)

  • Common ragweed
    • ALS resistant (2016)
  • Horseweed (marestail)
    • Triazine resistant (2001)


Grand Traverse Co. (back to map)

  • Horseweed (marestail)
    • Glyphosate resistant (2016)

 

Gratiot Co. (back to map)

  • Common lambsquarters
    • ALS resistant (2010)
  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2016)
  • Giant foxtail
    • ALS resistant (2006)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2014)
    • ALS resistant (2016)
    • Glyphosate resistant (2010)
    • Triazine resistant (2003)
  • Palmer amaranth
    • Multiple resistant- ALS & glyphosate (2013)
    • ALS resistant (2012)
    • Glyphosate resistant (2013)
  • Powell amaranth
    • ALS resistant (2016)


Hillsdale Co. (back to map)

  • Common ragweed
    • ALS resistant (2008)
  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2017)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2015)
  • Palmer amaranth
    • Multiple resistant- ALS & glyphosate (2017)
  • Wild carrot
    • Synthetic auxin resistant (1993)


Huron Co. (back to map)

  • Common lambsquarters
    • Triazine resistant (1980)
  • Common ragweed
    • Multiple resistant- ALS & PPO (2016)
    • ALS resistant (2011)
  • Eastern black nightshade
    • ALS resistant (2016)
  • Powell amaranth
    • ALS resistant (2008)


Ingham Co. (back to map)

  • Common groundsel
    • Triazine resistant (1990)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2016)
    • ALS resistant (2011)
  • Powell amaranth
    • ALS resistant (2016)
  • Wild carrot
    • Synthetic auxin resistant (1993)


Ionia Co. (back to map)

  • Common waterhemp
    • ALS resistant (2013)
  • Horseweed (marestail)
    • Glyphosate resistant (2011)


Isabella Co. (back to map)

  • Common ragweed
    • Multiple resistant- ALS & glyphosate (2014)
    • ALS resistant (2017)
  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2011)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2017)
    • ALS resistant (2014)
    • Glyphosate resistant (2011)
  • Powell amaranth
    • ALS resistant (2008)
  • Redroot pigweed
    • ALS resistant (2014)


Kent Co. (back to map)

  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2016)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2016)
    • Glyphosate resistant (2016)
    • ALS resistant (2016)


Lapeer Co. (back to map)

  • Common purslane
    • Multiple resistant- Triazine & ureas/amide (1991)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2011)


Leelanau Co. (back to map)

  • Horseweed (marestail)
    • Glyphosate resistant (2016)


Lenawee Co. (back to map)

  • Common purslane
    • Multiple resistant- Triazine & ureas/amide (1991)
  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2017)
    • Glyphosate resistant (2017)
  • Giant ragweed
    • Glyphosate resistant (2017)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2011)


Macomb Co. (back to map)

  • Giant ragweed
    • Glyphosate resistant (2016)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2015)


Manistee Co. (back to map)

  • Common lambsquarters
    • Triazine resistant (2006)
  • Redroot pigweed
    • Ureas/amide (2017)


Mason Co. (back to map)

  • Common ragweed
    • ALS resistant (2011)
  • Horseweed (marestail)
    • Glyphosate resistant (2007)
  • Redroot pigweed
    • Multiple resistant- ALS & ureas/amide (2017)


Missaukee Co. (back to map)

  • Common lambsquarters
    • Triazine resistant (2006)
  • Horseweed (marestail)
    • Triazine resistant (2004)


Monroe Co. (back to map)

  • Giant ragweed
    • Glyphosate resistant (2017)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2013)
    • Glyphosate resistant (2012)


Montcalm Co. (back to map)

  • Common lambsquarters
    • Triazine resistant (2006)
  • Common ragweed
    • ALS resistant (2011)
    • Synthetic auxin resistant (2017)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2014)
    • ALS resistant (2011)
    • Glyphosate resistant (2010)
    • Triazine resistant (2004)
  • Powell amaranth
    • Triazine resistant (2006)
  • Velvetleaf
    • Triazine resistant (2004)


Montmorency Co. (back to map)

  • Common ragweed
    • Glyphosate resistant (2017)


Newwaygo Co. (back to map)

  • Powell amaranth
    • ALS resistant (2015)


Oakland Co. (back to map)

  • Common lambsquarters
    • Triazine resistant (2006)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2015)


Oceana Co. (back to map)

  • Common ragweed
    • ALS resistant (2013)
  • Horseweed (marestail)
    • ALS resistant (2004)
    • Triazine resistant (2006)
  • Powell amaranth
    • Multiple resistant- ALS & ureas/amide (2017)
    • Multiple resistant- Triazine & ureas/amide (1981)
    • ALS resistant (2017)
    • Triazine resistant (2006)
  • Redroot pigweed –
    • Multiple resistant- ALS & ureas/amide (2017)
    • Multiple resistant- Triazine & ureas/amide (1981)


Ottawa Co. (back to map)

  • Common lambsquarters
    • ALS resistant (2016)
  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2016)
  • Horseweed (marestail)
    • Glyphosate resistant (2016)


Presque Isle Co. (back to map)

  • Horseweed (marestail)
    • ALS resistant (2017)


Saginaw Co. (back to map)

  • Common lambsquarters
    • ALS resistant (2015)
  • Common ragweed
    • Multiple resistant- ALS & glyphosate (2015)
    • Multiple resistant- ALS & PPO (2016)
    • ALS resistant (2015)
  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2014)
    • Multiple resistant- ALS & triazine (2015)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2015)
  • Kochia
    • ALS resistant (2005)
  • Powell amaranth
    • ALS resistant (2015)


Sanilac Co. (back to map)

  • Common lambsquarters
    • ALS resistant (2015)
  • Common ragweed
    • Multiple resistant- ALS & glyphosate (2014)
  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2015)
  • Horseweed (marestail)
    • Glyphosate resistant (2011)
  • Powell amaranth
    • ALS resistant (2015)


Shiawassee Co. (back to map)

  • Common ragweed
    • Multiple resistant- ALS & glyphosate (2014)
  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2014)
    • ALS resistant (2014)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2015)
    • Glyphosate resistant (2013)
  • Palmer amaranth
    • Multiple resistant- ALS & glyphosate (2011)
    • ALS resistant (2014)
  • Powell amaranth
    • Multiple resistant- ALS & triazine (2006)
    • ALS resistant (2011)


St. Clair Co.(back to map)

  • Common waterhemp
    • Multiple resistant- ALS & triazine (2015)
    • ALS resistant (2009)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2015)
  • Wild carrot
    • Synthetic auxin resistant (1993)


St. Joseph Co. (back to map)

  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2014)
  • Palmer amaranth
    • Multiple resistant- ALS & glyphosate (2012)
    • Glyphosate resistant (2010)


Tuscola Co. (back to map)

  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2016)
    • ALS resistant (2015)
  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2016)
  • Powell amaranth
    • ALS resistant (2016)


Van Buren Co. (back to map)

  • Common ragweed
    • ALS resistant (2004)
  • Horseweed (marestail)
    • Multiple resistant- ALS & Triazine (2004)
    • ALS resistant (2005)
  • Ladysthumb
    • Triazine resistant (2001)
  • Velvetleaf
    • Triazine resistant (2004)


Washtenaw Co. (back to map)

  • Horseweed (marestail)
    • Multiple resistant- ALS & glyphosate (2011)
    • Glyphosate resistant (2011)


Wayne Co. (back to map)

  • Common waterhemp
    • Multiple resistant- ALS & glyphosate (2015)


Wexford Co. (back to map)

  • Horseweed (marestail)
    • Triazine resistant (2006)

 

Other Confirmed Cases from Unknown Michigan Counties  (back to map)

  • Common ragweed
    • Triazine resistant (1990)
  • Eastern black nightshade
    • Triazine resistant (2004)
  • Halberdleaf orach
    • Triazine resistant (2003)
  • Lateflowering goosefoot
    • Triazine resistant (2004)
  • Marestail
    • Multiple resistant- Triazine & ureas/amide (2002)
    • Ureas/amide resistant (2002)
  • Smooth pigweed
    • ALS resistant (2002)