International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
(Bromus diandrus)

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

Australia, South Australia
Ripgut Brome (Bromus diandrus) is a monocot weed in the Poaceae family.  In South Australia this weed first evolved resistance to Group 2 (Legacy B) herbicides in 2011 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 mesosulfuron-methyl, and 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.

If we do not have a picture for this weed, or you can provide a better picture (scan, digital camera etc) please please e-mail it to us.

QUIK STATS (last updated Nov 30, 2011 )

Common NameRipgut Brome
SpeciesBromus diandrus
GroupInhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicidesmesosulfuron-methyl, and pyroxsulam
LocationAustralia, South Australia
Contributors - (Alphabetically)Peter Boutsalis 
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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.

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 South Australia please update the database.
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Postdoctural Fellow/ Consultant
University Of Adelaide / Plant Science Consulting
Plant And Pest Science
800 N Lindbergh Blvd
Adelaide, 5064, South Australia
Email Peter Boutsalis


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in South Australia have been instrumental in providing you this information. Particular thanks is given to Peter Boutsalis 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 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
Literature about Similar Cases

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