(Capsella bursa-pastoris)

ALS inhibitors (B/2)

Canada, Saskatchewan
Shepherd's-purse (Capsella bursa-pastoris) is a dicot weed in the Brassicaceae family.  In Saskatchewan this weed first evolved resistance to Group B/2 herbicides in 2008 and infests Wheat.   Group B/2 herbicides are known as ALS inhibitors (Inhibition of Acetolactate Synthase ).  Research has shown that these particular biotypes are resistant to imazamox, imazethapyr, thifensulfuron-methyl, and tribenuron-methyl and they may be cross-resistant to other Group B/2 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 08, 2010 )

Common NameShepherd's-purse
SpeciesCapsella bursa-pastoris
GroupALS inhibitors (B/2)
Herbicidesimazamox, imazethapyr, thifensulfuron-methyl, and tribenuron-methyl
LocationCanada, Saskatchewan
Contributors - (Alphabetically)Hugh Beckie 
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Confirmation Tests

Greenhouse trials comparing a known susceptible Shepherd's-purse biotype with this Shepherd's-purse 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 Group B/2 resistant Shepherd's-purse 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 B/2 resistant Shepherd's-purse from Saskatchewan please update the database.
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Research Scientist
Agriculture & Agri-Food Canada, Science & Technology Branch
Herbicide-Resistant & Novel-Trait Plants
107 Science Place
Saskatoon, S7N 0X2, Saskatchewan
Email Hugh Beckie


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Saskatchewan have been instrumental in providing you this information. Particular thanks is given to Hugh Beckie for providing detailed information.
Herbicide Resistant Shepherd's-purse Globally
(Capsella bursa-pastoris)
Herbicide Resistant Shepherd's-purse Globally
(Capsella bursa-pastoris)
Drag a column header and drop it here to group by that column
Herbicide Resistant Shepherd's-purse Globally
(Capsella bursa-pastoris)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Canada (Saskatchewan) CanadaSaskatchewan2008 Wheat imazamox, imazethapyr, thifensulfuron-methyl, and tribenuron-methyl 7 ALS inhibitors (B/2)
41Capsella bursa-pastorisShepherd's-purse5381
2 Canada (Alberta) CanadaAlberta2011 Wheat thifensulfuron-methyl, and tribenuron-methyl 7 ALS inhibitors (B/2)
41Capsella bursa-pastorisShepherd's-purse5623
3 ChinaChina 2009 Winter wheat tribenuron-methyl 9 ALS inhibitors (B/2)
41Capsella bursa-pastorisShepherd's-purse5502
4 DenmarkDenmark 2012 Spring Barley florasulam, and tribenuron-methyl 13 ALS inhibitors (B/2)
41Capsella bursa-pastorisShepherd's-purse8910
5 IsraelIsrael 2000 Roadsides imazapyr 23 ALS inhibitors (B/2)
41Capsella bursa-pastorisShepherd's-purse5465
6 NorwayNorway 2019 Wheat iodosulfuron-methyl-sodium 31 ALS inhibitors (B/2)
41Capsella bursa-pastorisShepherd's-purse18169
7 PolandPoland 1984 Orchards simazine 33 Photosystem II- Serine 264 Binders (C1/5)
41Capsella bursa-pastorisShepherd's-purse166
8 United States (Oregon) United StatesOregon2007 Alfalfa hexazinone, and metribuzin 45 Photosystem II- Serine 264 Binders (C1/5)
41Capsella bursa-pastorisShepherd's-purse5366
Literature about Similar Cases

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PERMISSION MUST BE OBTAINED FIRST if you intend to base a significant portion of a scientific paper on data derived from this site. Citation:
Heap, I.  The International Herbicide-Resistant Weed Database.  Online.  Saturday, April 10, 2021 .  Available Copyright © 1993- 2021 All rights reserved. Fair use of this material is encouraged. Proper citation is requested.