INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 1 (LEGACY A) RESISTANT FOXTAIL BARLEY
(Hordeum jubatum)

Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)

Canada, Alberta
INTRODUCTION FOXTAIL BARLEY
Foxtail Barley (Hordeum jubatum) is a monocot weed in the Poaceae family.  In Alberta this weed first evolved resistance to Group 1 (Legacy A) herbicides in 2022 and infests Creeping Red Fescue.   Group 1 (Legacy A) herbicides are known as Inhibition of Acetyl CoA Carboxylase (Inhibition of Acetyl CoA Carboxylase ).  Research has shown that these particular biotypes are resistant to quizalofop-ethyl and they may be cross-resistant to other Group 1 (Legacy A) 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 Jun 29, 2023 )

Common NameFoxtail Barley
SpeciesHordeum jubatum
GroupInhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
Herbicidesquizalofop-ethyl
LocationCanada, Alberta
Year2022
Situation(s)Creeping Red Fescue
Contributors - (Alphabetically)Charles Geddes 
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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Foxtail Barley biotype with this Foxtail Barley 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 1 resistant Foxtail Barley 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 1 (Legacy A) resistant Foxtail Barley from Alberta please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

CHARLES GEDDES
Research Scientist
Agriculture and Agri-Food Canada
Weed Ecology and Cropping Systems
Science and Technology Branch
Lethbridge Research and Development Centre 5403 - 1st Avenue South Lethbridge
Lethbridge, T1J481, Alberta
Canada
Email Charles Geddes

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 Charles Geddes for providing detailed information.
Herbicide Resistant Foxtail Barley Globally
(Hordeum jubatum)
Herbicide Resistant Foxtail Barley Globally
(Hordeum jubatum)
Drag a column header and drop it here to group by that column
Herbicide Resistant Foxtail Barley Globally
(Hordeum jubatum)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Canada (Alberta) CanadaAlberta2022 Creeping Red Fescue quizalofop-ethyl 7 Inhibition of Acetyl CoA Carboxylase ( HRAC Group 1 (Legacy A)
 		358Hordeum jubatumFoxtail Barley25263
Literature about Similar Cases

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HRAC Global Heap, I.  The International Herbicide-Resistant Weed Database.  Online.  Wednesday, September 23, 2026.  Available at  www.weedscience.org

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