INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 2 (LEGACY B) RESISTANT NARROWLEAF HAWKSBEARD
(Crepis tectorum)

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

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 2 (Legacy B) herbicides in 2011 and infests Grass seed.   Group 2 (Legacy B) herbicides are known as Inhibition of Acetolactate Synthase (Inhibition of Acetolactate Synthase ).  Research has shown that these particular biotypes are resistant to metsulfuron-methyl and they may be cross-resistant to other Group 2 (Legacy B) 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
GroupInhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
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 HRAC Group 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 2 (Legacy B) resistant Narrowleaf Hawksbeard from Alberta please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

HUGH BECKIE
Professor of Crop Weed Science...Canadian Expat
University of Western Australia
Australian Herbicide Resistance Initiative
School of Agriculture and Environment
35 Stirling Highway
Crawley, 6009, Western Australia
Australia
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 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
 		271Crepis tectorumNarrowleaf Hawksbeard5606
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Heap, I.  The International Herbicide-Resistant Weed Database.  Online.  Monday, April 15, 2024 .  Available  www.weedscience.org Copyright © 1993- 2024 WeedScience.org All rights reserved. Fair use of this material is encouraged. Proper citation is requested.