International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP B/2 RESISTANT MAYWEED CHAMOMILE
(Anthemis cotula)


ALS inhibitors (B/2)

United States, Idaho
INTRODUCTION MAYWEED CHAMOMILE
Mayweed Chamomile (Anthemis cotula) is a dicot weed in the Asteraceae family.  In Idaho this weed first evolved resistance to Group B/2 herbicides in 1997 and infests Canola, Cereals, Chickpea, Lentils, Peas, and Wheat.   Group B/2 herbicides are known as ALS inhibitors (Inhibition of acetolactate synthase ALS (acetohydroxyacid synthase AHAS)).  Research has shown that these particular biotypes are resistant to chlorsulfuron, imazethapyr, thifensulfuron-methyl, and tribenuron-methyl and they may be cross-resistant to other Group B/2 herbicides.

The 'Group' letters/numbers that you see throughout this web site refer to the classification of herbicides by their site of action. To see a full list of herbicides and HRAC herbicide classifications click here.

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QUIK STATS (last updated Dec 18, 2013 )

Common NameMayweed Chamomile
SpeciesAnthemis cotula
GroupALS inhibitors (B/2)
Herbicideschlorsulfuron, imazethapyr, thifensulfuron-methyl, and tribenuron-methyl
LocationUnited States, Idaho
Year1997
Situation(s)Canola, Cereals, Chickpea, Lentils, Peas, and Wheat
Contributors - (Alphabetically)Steven Seefeldt, and Donn Thill 
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NOTES ABOUT THIS BIOTYPE

GENERAL

Steven Seefeldt
DuPont tested. Resistant to 4X rates of chlorsulfuron in field. Dupont did the lab test.

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ACADEMIC ASPECTS

Confirmation Tests

Field, Greenhouse, and Laboratory trials comparing a known susceptible Mayweed Chamomile biotype with this Mayweed Chamomile biotype have been used to confirm resistance. For further information on the tests conducted please contact the local weed scientists that provided this information.
 
Genetics

Genetic studies on Group B/2 resistant Mayweed Chamomile have not been reported to the site.  There may be a note below or an article discussing the genetics of this biotype in the Fact Sheets and Other Literature
 
Mechanism of Resistance

The mechanism of resistance for this biotype is either unknown or has not been entered in the database.  If you know anything about the mechanism of resistance for this biotype then please update the database.
 
Relative Fitness

There is no record of differences in fitness or competitiveness of these resistant biotypes when compared to that of normal susceptible biotypes.  If you have any information pertaining to the fitness of Group B/2 resistant Mayweed Chamomile from Idaho please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

STEVEN SEEFELDT
Ruakura Agricultural Research Centre
Agresearch
Universidad Nacional La Plata
Casilla De Correo 31, Cátedra De Cereales
Hamilton
New Zealand
Email Steven Seefeldt
DONN THILL
Professor Of Weed Science
University Of Idaho
Plant, Soil
And Entomological Sciences
875 Perimeter Drive MS 2339
Moscow, 83844-2339, Idaho
United States
Email Donn Thill
Web   : Web Site Link

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Idaho have been instrumental in providing you this information. Particular thanks is given to Steven Seefeldt, and Donn Thill for providing detailed information.
Herbicide Resistant Mayweed Chamomile Globally
(Anthemis cotula)
Herbicide Resistant Mayweed Chamomile Globally
(Anthemis cotula)
Drag a column header and drop it here to group by that column
Herbicide Resistant Mayweed Chamomile Globally
(Anthemis cotula)
#CountryFirstYearSituationActive IngredientsSite of Action
1 ChileChile 2010 Wheat iodosulfuron-methyl-sodium, metsulfuron-methyl, and pyroxsulam 8 ALS inhibitors (B/2)
19Anthemis cotulaMayweed Chamomile5584
2 United States (Idaho) United StatesIdaho1997 Canola, Cereals, Chickpea, Lentils, Peas, and Wheat chlorsulfuron, imazethapyr, thifensulfuron-methyl, and tribenuron-methyl 45 ALS inhibitors (B/2)
19Anthemis cotulaMayweed Chamomile524
3 United States (Washington) United StatesWashington2010 Spring Barley, and Wheat cloransulam-methyl, imazethapyr, thifensulfuron-methyl, and tribenuron-methyl 45 ALS inhibitors (B/2)
19Anthemis cotulaMayweed Chamomile10987
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Cite this site as: Heap, I.  The International Survey of Herbicide Resistant Weeds.  Online.  Internet.  Saturday, September 21, 2019 .  Available  www.weedscience.org
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