(Galium aparine)

ALS inhibitors (B/2)

Catchweed Bedstraw (Galium aparine) is a dicot weed in the Rubiaceae family.  In China this weed first evolved resistance to Group B/2 herbicides in 2007 and infests Winter wheat.   Group B/2 herbicides are known as ALS inhibitors (Inhibition of Acetolactate Synthase ).  Research has shown that these particular biotypes are resistant to 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.

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QUIK STATS (last updated Mar 11, 2013 )

Common NameCatchweed Bedstraw
SpeciesGalium aparine
GroupALS inhibitors (B/2)
Situation(s)Winter wheat
Contributors - (Alphabetically)Jinxin Wang 
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Confirmation Tests

Field, Greenhouse, and Laboratory trials comparing a known susceptible Catchweed Bedstraw biotype with this Catchweed Bedstraw 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 Catchweed Bedstraw 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

Studies on the mechanism of resistance of Group B/2 resistant Catchweed Bedstraw from China indicate that resistance is due to an altered target site.  There may be a note below or an article discussing the mechanism of resistance in the Fact Sheets and Other Literature
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 Catchweed Bedstraw from China please update the database.
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Shandong Agricultural University
College Of Plant Protection
Daizong Road 61#
Tai'an, 271018, Shandong
Email Jinxin Wang


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in China have been instrumental in providing you this information. Particular thanks is given to Jinxin Wang for providing detailed information.
Herbicide Resistant Catchweed Bedstraw Globally
(Galium aparine)
Herbicide Resistant Catchweed Bedstraw Globally
(Galium aparine)
Drag a column header and drop it here to group by that column
Herbicide Resistant Catchweed Bedstraw Globally
(Galium aparine)
#CountryFirstYearSituationActive IngredientsSite of Action
1 ChinaChina 2007 Winter wheat tribenuron-methyl 9 ALS inhibitors (B/2)
272Galium aparineCatchweed Bedstraw5607
2 ChinaChina 2014 Wheat fluroxypyr 9 Auxin Mimics (O/4)
272Galium aparineCatchweed Bedstraw10952
3 IranIran 2016 Wheat 2,4-D, and MCPA 79 Auxin Mimics (O/4)
272Galium aparineCatchweed Bedstraw16083
4 IranIran 2017 Wheat tribenuron-methyl 79 ALS inhibitors (B/2)
272Galium aparineCatchweed Bedstraw15064
5 IranIran 2017 Wheat 2,4-D, iodosulfuron-methyl-sodium, MCPA, mesosulfuron-methyl, sulfosulfuron, and tribenuron-methyl 79 Multiple Resistance: 2 Sites of Action
ALS inhibitors (B/2)
Auxin Mimics (O/4)
272Galium aparineCatchweed Bedstraw17138
6 TurkeyTurkey 2008 Winter wheat chlorsulfuron, iodosulfuron-methyl-sodium, mesosulfuron-methyl, thifensulfuron-methyl, triasulfuron, and tribenuron-methyl 71 ALS inhibitors (B/2)
272Galium aparineCatchweed Bedstraw7814
Literature about Similar Cases

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Heap, I.  The International Herbicide-Resistant Weed Database.  Online.  Saturday, April 17, 2021 .  Available Copyright © 1993- 2021 All rights reserved. Fair use of this material is encouraged. Proper citation is requested.