Catchweed Bedstraw (Galium aparine) is a dicot weed in the Rubiaceae family.  In Iran this weed first evolved resistance to Group B/2 herbicides in 2017 and infests Wheat.   Group B/2 herbicides are known as ALS inhibitors (Inhibition of acetolactate synthase ALS (acetohydroxyacid synthase AHAS)).  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 Jul 28, 2017 )

Common NameCatchweed Bedstraw
SpeciesGalium aparine
GroupALS inhibitors (B/2)
LocationIran, Kermanshah province
Contributors - (Alphabetically)Bhagirath Chauhan, Iraj Nosratti, Peyman Sabeti, and Farhad Sharifi 
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Confirmation Tests

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

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 Catchweed Bedstraw from Iran please update the database.
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Principal Research Fellow & Weed Team Leader
The University of Queensland
Queensland Alliance for Agriculture and Food Innovation
Room 125, Building 8103
Post Box 1218
Gatton, 4343, Queensland
Email Bhagirath Chauhan
Web   : Web Site Link
Assistant Professor
Razi University
Department of Agronomy and Plant Breeding
Fac. of Science and Ag Engineering
Tazeh Abad
Kermanshah, 67149-67346, Kermanshah Province
Email Iraj Nosratti
Web   : Web Site Link
Weed Researcher
Kermanshah Agricultural and Natural Resources and Education Center
Plant Protection Research Department
Keshavarz Blvd.
Kermanshah, 67158483333, Kermanshah
Email Peyman Sabeti
Web   : Web Site Link
Manager of Plant Protection Organization of Kermanshah
Plant Protection Organization,Organization of Agriculture Jahad Kermanshah, Iran
Plant Protection Organization of Kermanshah
Keshavarz Blvd.
Kermanshah, 4833167158, Kermanshah
Email Farhad Sharifi
Web   : Web Site Link


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Iran have been instrumental in providing you this information. Particular thanks is given to Bhagirath Chauhan, Iraj Nosratti, Peyman Sabeti, and Farhad Sharifi 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 Synthetic Auxins (O/4)
272Galium aparineCatchweed Bedstraw10952
3 IranIran 2016 Wheat 2,4-D, and MCPA 79 Synthetic Auxins (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)
Synthetic Auxins (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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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.  Tuesday, October 20, 2020 .  Available Copyright © 1993- 2020 All rights reserved. Fair use of this material is encouraged. Proper citation is requested.