International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP B/2 RESISTANT NARROWLEAF HAWKSBEARD
(Crepis tectorum)


ALS inhibitors (B/2)

Canada, Alberta
INTRODUCTION NARROWLEAF HAWKSBEARD
Narrowleaf Hawksbeard (Crepis tectorum) is a dicot weed in the Asteraceae family.  In Alberta this weed first evolved resistance to Group B/2 herbicides in 2011 and infests Grass seed.   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 metsulfuron-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 Mar 20, 2012 )

Common NameNarrowleaf Hawksbeard
SpeciesCrepis tectorum
GroupALS inhibitors (B/2)
Herbicidesmetsulfuron-methyl
LocationCanada, Alberta
Year2011
Situation(s)Grass seed
Contributors - (Alphabetically)Hugh Beckie 
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NOTES ABOUT THIS BIOTYPE

GENERAL

Hugh Beckie
Investigated by C. Yoder, Forage Seed Specialist, AARD

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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Narrowleaf Hawksbeard biotype with this Narrowleaf Hawksbeard 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 Narrowleaf Hawksbeard 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 Narrowleaf Hawksbeard from Alberta please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

HUGH BECKIE
Research Scientist
Agriculture & Agri-Food Canada, Science & Technology Branch
Herbicide-Resistant & Novel-Trait Plants
107 Science Place
Saskatoon, S7N 0X2, Saskatchewan
Canada
Email Hugh Beckie

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Alberta have been instrumental in providing you this information. Particular thanks is given to Hugh Beckie for providing detailed information.
Herbicide Resistant Narrowleaf Hawksbeard Globally
(Crepis tectorum)
Herbicide Resistant Narrowleaf Hawksbeard Globally
(Crepis tectorum)
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Herbicide Resistant Narrowleaf Hawksbeard Globally
(Crepis tectorum)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Canada (Alberta) CanadaAlberta2011 Grass seed metsulfuron-methyl 7 ALS inhibitors (B/2)
271Crepis tectorumNarrowleaf Hawksbeard5606
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Cite this site as: Heap, I.  The International Survey of Herbicide Resistant Weeds.  Online.  Internet.  Friday, October 20, 2017 .  Available  www.weedscience.org
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