International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
(Camelina microcarpa)

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

United States, Oregon
Smallseed Flaxfalse (Camelina microcarpa) is a dicot weed in the Brassicaceae family.  In Oregon this weed first evolved resistance to Group 2 (Legacy B) herbicides in 1999 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 chlorsulfuron, and 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.

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 Feb 04, 2002 )

Common NameSmallseed Flaxfalse
SpeciesCamelina microcarpa
GroupInhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicideschlorsulfuron, and metsulfuron-methyl
LocationUnited States, Oregon
Contributors - (Alphabetically)Brad Hanson 
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Confirmation Tests

Field, and Greenhouse trials comparing a known susceptible Smallseed Flaxfalse biotype with this Smallseed Flaxfalse 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 Smallseed Flaxfalse 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 Smallseed Flaxfalse from Oregon please update the database.
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Cooperative Extension Weed Specialist
University Of California, Davis
Department Of Plant Sciences
MS-4, One Shields Ave
276 Robbins Hall
Davis, 91616, California
United States
Email Brad Hanson
Web   : Web Site Link


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Oregon have been instrumental in providing you this information. Particular thanks is given to Brad Hanson for providing detailed information.
Herbicide Resistant Smallseed Flaxfalse Globally
(Camelina microcarpa)
Herbicide Resistant Smallseed Flaxfalse Globally
(Camelina microcarpa)
Drag a column header and drop it here to group by that column
Herbicide Resistant Smallseed Flaxfalse Globally
(Camelina microcarpa)
#CountryFirstYearSituationActive IngredientsSite of Action
1 United States (Oregon) United StatesOregon1999 Wheat chlorsulfuron, and metsulfuron-methyl 45 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
207Camelina microcarpaSmallseed Flaxfalse5111
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