Herbicide Resistant Weeds

Thursday, September 09, 2010

What's on this page

Tall Waterhemp

1.	Resistant Weeds of Missouri
2.	Resistance in Neighboring States
3.	Fact Sheets & Literature
4.	Resistance Experts in Missouri
5.	Contributing Weed Scientists
6.	Acknowledgements
7.	Where to now?

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Tall Waterhemp (Amaranthus tuberculatus (syn. rudis)) is the most widespread resistant weed of Missouri

Introduction

About this page

There are currently 12 different types (known as 'biotypes') of herbicide resistant weeds in Missouri. The first herbicide resistant weed reported from Missouri is Common cocklebur (Xanthium strumarium) with resistance to chlorimuron-ethyl, and imazaquin, reported in 1992. Local weed scientists estimate that there are 6,980 sites and more than 4,177,200 acres infested with herbicide resistant weeds in Missouri and they infest corn, cotton, rice, and soybean. The most widespread resistant weed of Missouri is Tall Waterhemp (Amaranthus tuberculatus (syn. rudis)), which infests an estimated 2-5 million acres and is found primarily in soybean. Giant Ragweed (Ambrosia trifida), with resistance to glyphosate is the most recently discovered (2009) new type of resistant weed in Missouri.

This is a resource page to assist you in managing herbicide-resistant weeds in Missouri . If you have any questions regarding herbicide-resistant weeds in Missouri please contact an expert in your area. If you have encountered a computer related error on the site then contact support@weedscience.org. If you are a weed scientist wanting to add or correct information on this page then please contact research@weedscience.org or add the information directly.

Scroll down this page to view tables on herbicide resistant weeds in Missouri and its adjacent states as well as a list of articles about herbicide resistant weeds in your region. Click on the links within the table to view a case of resistance in more detail.

HERBICIDE RESISTANT WEEDS IN MISSOURI
Weed	Situation	Herbicide Mode of Action	Year
Common cocklebur (Xanthium strumarium)	soybean	B/2 - ALS inhibitors (chlorimuron-ethyl, imazaquin)	1992
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	corn	C1/5 - Photosystem II inhibitors (atrazine)	1994
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	soybean	B/2 - ALS inhibitors (chlorimuron-ethyl, flumetsulam, halosulfuron-methyl, imazamox, imazaquin, imazethapyr, nicosulfuron, primisulfuron-methyl, prosulfuron, thifensulfuron-methyl)	1994
Barnyardgrass (Echinochloa crus-galli)	rice	C2/7 - Ureas and amides (propanil)	1994
Common Sunflower (Helianthus annuus)	soybean	B/2 - ALS inhibitors (chlorimuron-ethyl, cloransulam-methyl, flumetsulam, halosulfuron-methyl, imazaquin, imazethapyr, oxasulfuron)	1996
Horseweed (Conyza canadensis)	cotton	G/9 - Glycines (glyphosate)	2002
Common Ragweed (Ambrosia artemisiifolia)	soybean	G/9 - Glycines (glyphosate)	2004
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	corn, soybean	B/2 - ALS inhibitors (acifluorfen-Na, cloransulam-methyl, fomesafen, glyphosate, imazamox, imazethapyr, lactofen)	2005
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	corn, soybean	E/14 - PPO inhibitors (acifluorfen-Na, cloransulam-methyl, fomesafen, glyphosate, imazamox, imazethapyr, lactofen)	2005
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	corn, soybean	G/9 - Glycines (acifluorfen-Na, cloransulam-methyl, fomesafen, glyphosate, imazamox, imazethapyr, lactofen)	2005
Palmer Amaranth (Amaranthus palmeri)	cotton, soybean	G/9 - Glycines (glyphosate)	2008
Giant Ragweed (Ambrosia trifida)	soybean	G/9 - Glycines (glyphosate)	2009

HERBICIDE RESISTANT WEEDS IN ADJACENT STATES

ARKANSAS
Species	MOA	Year
Goosegrass	K1/3	1989
Common cocklebur	Z/17	1989
Barnyardgrass	C2/7	1990
Palmer Amaranth	B/2	1994
Redroot Pigweed	B/2	1995
Italian Ryegrass	A/1	1995
Italian Ryegrass	B/2	1995
Common cocklebur	B/2	1995
Barnyardgrass	C2/7	1999
Barnyardgrass	O/4	1999
Horseweed	G/9	2003
Italian Ryegrass	B/2	2003
Common Ragweed	G/9	2004
Giant Ragweed	G/9	2005
Italian Ryegrass	A/1	2005
Palmer Amaranth	G/9	2006
Johnsongrass	G/9	2007
Italian Ryegrass	A/1	2008
Italian Ryegrass	B/2	2008
Italian Ryegrass	G/9	2008

IOWA
Species	MOA	Year
Kochia	C1/5	1985
Lambsquarters	C1/5	1989
Pennsylvania smartweed	C1/5	1990
Giant Foxtail	C1/5	1992
Tall Waterhemp	B/2	1993
Giant Foxtail	A/1	1994
Common cocklebur	B/2	1995
Tall Waterhemp	C1/5	1996
Common Sunflower	B/2	1997
Shattercane	B/2	1998
Giant Ragweed	B/2	2000
Tall Waterhemp	B/2	2009
Tall Waterhemp	C1/5	2009
Tall Waterhemp	E/14	2009
Tall Waterhemp	E/14	2009
Tall Waterhemp	F2/27	2009
Tall Waterhemp	G/9	2009
Giant Ragweed	G/9	2009

ILLINOIS
Species	MOA	Year
Lambsquarters	C1/5	1985
Kochia	C1/5	1992
Smooth Pigweed	C1/5	1993
Tall Waterhemp	B/2	1993
Kochia	B/2	1995
Kochia	C1/5	1995
Tall Waterhemp	B/2	1996
Tall Waterhemp	C1/5	1996
Common Ragweed	B/2	1998
Giant Ragweed	B/2	1998
Eastern Black Nightshade	B/2	1999
Tall Waterhemp	C1/5	2001
Tall Waterhemp	B/2	2002
Tall Waterhemp	C1/5	2002
Tall Waterhemp	E/14	2002
Horseweed	G/9	2005
Tall Waterhemp	B/2	2006
Tall Waterhemp	G/9	2006
Tall Waterhemp	B/2	2009
Tall Waterhemp	C1/5	2009
Tall Waterhemp	F2/27	2009

KANSAS
Species	MOA	Year
Field Bindweed	O/4	1964
Kochia	C1/5	1976
Kochia	B/2	1987
Palmer Amaranth	B/2	1991
Palmer Amaranth	C1/5	1995
Redroot Pigweed	C1/5	1995
Tall Waterhemp	B/2	1995
Tall Waterhemp	C1/5	1995
Common Sunflower	B/2	1996
Shattercane	B/2	1996
Common cocklebur	B/2	1997
Tall Waterhemp	B/2	2001
Tall Waterhemp	E/14	2001
Horseweed	G/9	2005
Bushy Wallflower	B/2	2005
Tall Waterhemp	G/9	2006
Giant Ragweed	G/9	2006
Flixweed	B/2	2006
Common Ragweed	G/9	2007
Japanese Brome	B/2	2007
Rye Brome	B/2	2007
Kochia	G/9	2007
Kochia	G/9	2007

KENTUCKY
Species	MOA	Year
Smooth Pigweed	C1/5	1987
Johnsongrass	A/1	1991
Smooth Pigweed	B/2	1992
Horseweed	G/9	2001

NEBRASKA
Species	MOA	Year
Shattercane	B/2	1994
Tall Waterhemp	C1/5	1996

OKLAHOMA
Species	MOA	Year
Kochia	B/2	1992
Common cocklebur	B/2	1996
Tall Waterhemp	B/2	2002

TENNESSEE
Species	MOA	Year
Goosegrass	K1/3	1988
Common cocklebur	Z/17	1991
Common cocklebur	B/2	1992
Johnsongrass	A/1	1995
Lambsquarters	C1/5	1998
Horseweed	G/9	2001
Palmer Amaranth	B/2	2006
Palmer Amaranth	G/9	2006
Palmer Amaranth	G/9	2006
Italian Ryegrass	A/1	2006
Tall Waterhemp	B/2	2007
Giant Ragweed	G/9	2007

FACT SHEETS AND OTHER LITERATURE	Format

Herbicide Resistance in Weeds. Andrew Kendig, and Fred Fishel (1996) University of Missouri In 1992 no known herbicide-resistant weeds existed in Missouri. In 1994 there were more than five sites. Herbicide-resistant weeds are populations that were previously controlled by a particular herbicide but are no longer controlled by a normal rate of application for that herbicide. Much time is spent arguing about terminology: Is johnsongrass resistant to atrazine? Is pigweed resistant to Assure, Bugle, Fusilade, Poast and Select? Johnsongrass always has been resistant to atrazine, and, likew.	HTM

Herbicide Resistance in Weeds - pdf. Andrew Kendig, and Fred Fishel (1996) In 1992 no known herbicide-resistant weeds existed in Missouri. In 1994 there were more than five sites. Herbicide-resistant weeds are populations that were previously controlled by a particular herbicide but are no longer controlled by a normal rate of application for that herbicide. Much time is spent arguing about terminology: Is johnsongrass resistant to atrazine? Is pigweed resistant to Assure, Bugle, Fusilade, Poast and Select? Johnsongrass always has been resistant to atrazine, and, likew.	PDF

HERBICIDE RESISTANT WEED CONTACTS IN MISSOURI

Your local state university extension agent or local department of agriculture representative may be able to provide you with more information on herbicide-resistant weeds in your region. Much of the information about herbicide-resistant weeds in Missouri has been provided by the following experts.

STATE CONTACTS

KEVIN BRADLEY

Asst. Professor & Extension Weed Scientist
University of Missouri
Division of Plant Sciences
206A Waters Hall
Columbia, 65211, Missouri
United States of America
Phone : 573-882-4039
Fax : 573-882-1467
Email Kevin Bradley
Web : Web Site Link

ANDY KENDIG

University of Missouri
Delta Center
P.O. Box 160, Old US. 61 South
Portageville, 63873, Missouri
United States of America
Phone : (573) 379-4031
Fax : (573) 379-5875
Email Andy Kendig

ALEJANDRO PEREZ-JONES

Weed Research Specialist
Monsanto
Chemistry Technology
800 N Lindbergh Blvd.
St. Louis, 63167, Missouri
United States of America
Phone : (314) 694-7153
Email Alejandro Perez-Jones

REID SMEDA

Assistant Professor - Weed Physiologist
University of Missouri-Columbia
Agronomy
202 Waters Hall
Columbia, 65211, Missouri
United States of America
Phone : 573-882-2001
Fax : 573-884-4713
Email Reid Smeda

Acknowledgements

Where to now?

The North American Herbicide Resistance Action Committee and weed scientists in Missouri have been instrumental in providing you this information. Particular thanks is given to Kevin Bradley , Andy Kendig, Alejandro Perez-Jones, and Reid Smeda for providing detailed information.

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