INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 2 (LEGACY B) RESISTANT RIPGUT BROME
(Bromus diandrus)


Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

New Zealand, North Otago
INTRODUCTION RIPGUT BROME
Ripgut Brome (Bromus diandrus) is a monocot weed in the Poaceae family.  In New Zealand this weed first evolved resistance to Group 2 (Legacy B) herbicides in 2024 and infests Wheat.   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 pyroxsulam 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 Jan 21, 2024 )

Common NameRipgut Brome
SpeciesBromus diandrus
GroupInhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicidespyroxsulam
LocationNew Zealand, North Otago
Year2024
Situation(s)Wheat
Contributors - (Alphabetically)Chris Buddenhagen, and Zachary Ngow 
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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Ripgut Brome biotype with this Ripgut Brome 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 Ripgut Brome 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 Ripgut Brome from New Zealand please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

CHRIS BUDDENHAGEN
AgResearch
10 Bisley Rd
Ruakura
Hamilton, 3216, Waikato
New Zealand
Email Chris Buddenhagen
ZACHARY NGOW
Technician
AgResearch Ltd.
Agro-ecology
10 Bisley Road
Ruakura
Hamilton, 3214, Waikato
New Zealand
Email Zachary Ngow
Web   : Web Site Link

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in New Zealand have been instrumental in providing you this information. Particular thanks is given to Chris Buddenhagen, and Zachary Ngow for providing detailed information.
Herbicide Resistant Ripgut Brome Globally
(Bromus diandrus)
Herbicide Resistant Ripgut Brome Globally
(Bromus diandrus)
Drag a column header and drop it here to group by that column
Herbicide Resistant Ripgut Brome Globally
(Bromus diandrus)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Australia (Victoria) AustraliaVictoria1999 Cereals, and Winter pulses clethodim, fluazifop-butyl, haloxyfop-methyl, quizalofop-ethyl, and tepraloxydim 1 Inhibition of Acetyl CoA Carboxylase ( HRAC Group 1 (Legacy A)
197Bromus diandrusRipgut Brome5467
2 Australia (South Australia) AustraliaSouth Australia2011 Wheat mesosulfuron-methyl, and pyroxsulam 1 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
197Bromus diandrusRipgut Brome5580
3 Australia (South Australia) AustraliaSouth Australia2011 Fencelines, and Wheat glyphosate 1 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase ( HRAC Group 9 (Legacy G)
197Bromus diandrusRipgut Brome5597
4 Australia (Western Australia) AustraliaWestern Australia2020 Canola clethodim, and quizalofop-ethyl 1 Inhibition of Acetyl CoA Carboxylase ( HRAC Group 1 (Legacy A)
197Bromus diandrusRipgut Brome26262
5 New ZealandNew Zealand 2024 Wheat pyroxsulam 30 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
197Bromus diandrusRipgut Brome27283
6 United KingdomUnited Kingdom 2020 Wheat iodosulfuron-methyl-Na, mesosulfuron-methyl, and pyroxsulam 44 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
197Bromus diandrusRipgut Brome25256
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Heap, I.  The International Herbicide-Resistant Weed Database.  Online.  Tuesday, October 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.