Herbicide Resistant Weeds

Thursday, September 09, 2010

What's on this page

Tall Waterhemp

1.	Resistant Weeds of Iowa
2.	Resistance in Neighboring States
3.	Fact Sheets & Literature
4.	Resistance Experts in Iowa
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 Iowa

Introduction

About this page

There are currently 18 different types (known as 'biotypes') of herbicide resistant weeds in Iowa. The first herbicide resistant weed reported from Iowa is Kochia (Kochia scoparia) with resistance to atrazine, reported in 1985. Local weed scientists estimate that there are 1,210 sites and more than 12,500 acres infested with herbicide resistant weeds in Iowa and they infest corn, railways, seed corn, and soybean. The most widespread resistant weed of Iowa is Tall Waterhemp (Amaranthus tuberculatus (syn. rudis)), which infests an estimated 1001-10000 acres and is found primarily in corn, and soybean. Giant Ragweed (Ambrosia trifida), with resistance to glyphosate is the most recently discovered (2009) new type of resistant weed in Iowa.

This is a resource page to assist you in managing herbicide-resistant weeds in Iowa . If you have any questions regarding herbicide-resistant weeds in Iowa 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 Iowa 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 IOWA
Weed	Situation	Herbicide Mode of Action	Year
Kochia (Kochia scoparia)	railways	C1/5 - Photosystem II inhibitors (atrazine)	1985
Lambsquarters (Chenopodium album)	corn	C1/5 - Photosystem II inhibitors (atrazine)	1989
Pennsylvania smartweed (Polygonum pensylvanicum)	corn	C1/5 - Photosystem II inhibitors (atrazine)	1990
Giant Foxtail (Setaria faberi)	corn	C1/5 - Photosystem II inhibitors (atrazine)	1992
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	corn, soybean	B/2 - ALS inhibitors (imazethapyr)	1993
Giant Foxtail (Setaria faberi)	soybean	A/1 - ACCase inhibitors (clethodim, fenoxaprop-P-ethyl, fluazifop-P-butyl, quizalofop-P-ethyl, sethoxydim)	1994
Common cocklebur (Xanthium strumarium)	soybean	B/2 - ALS inhibitors (chlorimuron-ethyl, imazethapyr)	1995
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	corn	C1/5 - Photosystem II inhibitors (atrazine)	1996
Common Sunflower (Helianthus annuus)	corn, soybean	B/2 - ALS inhibitors (chlorimuron-ethyl, imazethapyr)	1997
Shattercane (Sorghum bicolor)	corn	B/2 - ALS inhibitors (imazethapyr)	1998
Giant Ragweed (Ambrosia trifida)	corn, soybean	B/2 - ALS inhibitors (cloransulam-methyl, primisulfuron-methyl, prosulfuron)	2000
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	soybean	E/14 - PPO inhibitors (lactofen)	2009
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	soybean	E/14 - PPO inhibitors (lactofen)	2009
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	corn, soybean	G/9 - Glycines (glyphosate)	2009
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	seed corn	B/2 - ALS inhibitors (atrazine, mesotrione, rimsulfuron, tembotrione, thifensulfuron-methyl, topramezone)	2009
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	seed corn	C1/5 - Photosystem II inhibitors (atrazine, mesotrione, rimsulfuron, tembotrione, thifensulfuron-methyl, topramezone)	2009
Tall Waterhemp (Amaranthus tuberculatus (syn. rudis))	seed corn	F2/27 - 4-HPPD inhibitors (atrazine, mesotrione, rimsulfuron, tembotrione, thifensulfuron-methyl, topramezone)	2009
Giant Ragweed (Ambrosia trifida)	corn, soybean	G/9 - Glycines (glyphosate)	2009

HERBICIDE RESISTANT WEEDS IN ADJACENT STATES

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

MINNESOTA
Species	MOA	Year
Lambsquarters	C1/5	1982
Velvetleaf	C1/5	1991
Redroot Pigweed	C1/5	1991
Wild Oat	A/1	1991
Kochia	B/2	1994
Common cocklebur	B/2	1994
Giant Foxtail	B/2	1996
Robust White Foxtail	B/2	1996
Yellow Foxtail (lutescens)	B/2	1997
Common Ragweed	B/2	1998
Robust White Foxtail	A/1	1999
Purple Robust Foxtail	A/1	1999
Giant Ragweed	G/9	2006
Tall Waterhemp	G/9	2007

MISSOURI
Species	MOA	Year
Common cocklebur	B/2	1992
Tall Waterhemp	B/2	1994
Tall Waterhemp	C1/5	1994
Barnyardgrass	C2/7	1994
Common Sunflower	B/2	1996
Horseweed	G/9	2002
Common Ragweed	G/9	2004
Tall Waterhemp	B/2	2005
Tall Waterhemp	E/14	2005
Tall Waterhemp	G/9	2005
Palmer Amaranth	G/9	2008
Giant Ragweed	G/9	2009

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

SOUTH DAKOTA
Species	MOA	Year
Kochia	B/2	1988
Common Sunflower	B/2	1996

WISCONSIN
Species	MOA	Year
Lambsquarters	C1/5	1979
Smooth Pigweed	C1/5	1985
Kochia	C1/5	1987
Velvetleaf	C1/5	1990
Giant Foxtail	A/1	1991
Large Crabgrass	A/1	1992
Kochia	B/2	1995
Tall Waterhemp	B/2	1999
Giant Foxtail	B/2	1999
Green Foxtail	B/2	1999
Eastern Black Nightshade	B/2	1999

HERBICIDE RESISTANT WEED CONTACTS IN IOWA

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 Iowa has been provided by the following experts.

STATE CONTACTS

JACK DEKKER

Iowa State University
Agronomy Dept.
3214 Agronomy Hall
Ames, 50011, Iowa
United States of America
Phone : (515) 294-8229
Fax : (515) 294-3163
Email Jack Dekker

ROBERT HARTZLER

Iowa State University
2104 Agronomy Hall
Ames, 50011, Iowa
United States of America
Phone : (515) 294-1923
Fax : (515) 294-9985
Email Robert Hartzler

PATRICK MCMULLAN

Research Scientist
Pioneer Hi-Bred International
Crop Genetics Research & Development
7300 NW 62nd Ave
PO Box 1004
Johnston, 50131, Iowa
United States of America
Phone : 515-270-4261
Fax : 515-253-2388
Email Patrick McMullan

MICHEAL OWEN

Associate Chair and Professor
Iowa State University
Agronomy Department
3218 Agronomy Hall
Ames, 50011, Iowa
United States of America
Phone : (515) 294-5936
Fax : (515) 294-9985
Email Micheal Owen
Web : Web Site Link

IAN ZELAYA

Post�doctoral Research Associate
Iowa State University
Department of Agronomy
2104 Agronomy Hall
Ames, 50011-1011, Iowa
United States of America
Phone : +1-515-294�1923
Fax : +1-515-294�9985
Email Ian Zelaya

Acknowledgements

Where to now?

The North American Herbicide Resistance Action Committee and weed scientists in Iowa have been instrumental in providing you this information. Particular thanks is given to Jack Dekker, Robert Hartzler, Patrick McMullan, Micheal Owen, and Ian Zelaya for providing detailed information.

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