12 MIN READ

Weed Calendar for the Corn Belt

June 9, 2021

The differences in emergence characteristics of weed species are one of the reasons why weed management is such a difficult task. Knowing when weeds emerge can help improve weed management systems by increasing scouting efficiency and help determine optimum weed control tactic timing (seedbed prep, herbicide application, cultivation, etc).


Weed emergence sequence of common troublesome annual weed species in the Corn Belt growing region.
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Identification

Annual bluegrass. Photo courtesy of Shawn Wright, University of Kentucky, Bugwood.org.
Annual bluegrass. Photo courtesy of Shawn Wright, University of Kentucky, Bugwood.org.


Downy brome.
Downy brome.


Large crabgrass collar region. Photo courtesy of Steven Gower.
Large crabgrass collar region.


Large crabgrass seedhead.Photos courtesy of Steven Gower.
Large crabgrass seedhead.


Wooly cupgrass. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org.
Wooly cupgrass. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org.


Barnyardgrass. Photos courtesy of Bruce Ackley, The Ohio State University and Howard F Schwartz, Colorado State University, Bugwood.org.
Barnyardgrass. Photos courtesy of Bruce Ackley, The Ohio State University and Howard F Schwartz, Colorado State University, Bugwood.org.


Barnyardgrass. Photos courtesy of Bruce Ackley, The Ohio State University and Howard F Schwartz, Colorado State University, Bugwood.org.
Barnyardgrass. Photos courtesy of Bruce Ackley, The Ohio State University and Howard F Schwartz, Colorado State University, Bugwood.org.


Green foxtail. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org.
Green foxtail. Photo courtesy of Bruce Ackley, The Ohio State University, Bugwood.org.


Giant foxtail. Photo courtesy of John D. Byrd, Mississippi State University, Bugwood.org.
Giant foxtail. Photo courtesy of John D. Byrd, Mississippi State University, Bugwood.org.


Yellow foxtail. Photo courtesy of John D. Byrd, Mississippi State University, Bugwood.org
Yellow foxtail. Photo courtesy of John D. Byrd, Mississippi State University, Bugwood.org


Goosegrass. Photo courtesy of John D. Byrd, Mississippi State University, Bugwood.org.
Goosegrass. Photo courtesy of John D. Byrd, Mississippi State University, Bugwood.org.




Fall panicum.
Fall panicum.

Sources:

Aneson, N., Striegel, S. and Werle, R. Giant ragweed. Grow IWM. http://growiwm.org.

Bradley K. 2018. Morning glory management in soybean. Take Action Herbicide Resistance Management. Http://iwilltakeaction.com.

Curran, W.S. and Klodd, A. 2014. Invasive pigweeds: Palmer amaranth and waterhemp. Penn State Extension. http://extension.psu.edu.

Doll, JD. 2001. Knowing when to look for what: Weed emergence and flowering sequences in Wisconsin. Department of Agronomy. UW-Madison Wisconsin. http://extension.soils.wisc.edu.

Hartzler, RG. 2008. Relative emergence sequence for weeds of corn and soybean. Iowa State University. http://www.extension.iastate.edu/.

Pittman, K. Horseweed. Grow IWM. http://growiwm.org.

Sprague, C. 2020. Palmer amaranth management in soybeans. Take Action Herbicide Resistance Management. http://iwilltakeaction.com.

Steckel, L. 2019. Barnyardgrass management in soybeans. Take Action Herbicide Resistance Management. http://iwilltakeaction.com.


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The differences in emergence characteristics of weed species are one of the reasons why weed management is such a difficult task. Knowing when weeds emerge can help improve weed management systems by increasing scouting efficiency and help determine optimum weed control tactic timing (seedbed prep, herbicide application, cultivation, etc).


Weed emergence sequence of common troublesome annual weed species in the Corn Belt growing region.
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Disclaimer

Always read and follow pesticide label directions, insect resistance management requirements (where applicable), and grain marketing and all other stewardship practices.