INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 4 (LEGACY O) RESISTANT CANADA THISTLE
(Cirsium arvense)


Auxin Mimics HRAC Group 4 (Legacy O)

Sweden
INTRODUCTION CANADA THISTLE
Canada thistle (Cirsium arvense) is a dicot weed in the Asteraceae family.  In Sweden this weed first evolved resistance to Group 4 (Legacy O) herbicides in 1979 and infests Cropland.   Group 4 (Legacy O) herbicides are known as Auxin Mimics (Auxin Mimics ).  Research has shown that these particular biotypes are resistant to MCPA and they may be cross-resistant to other Group 4 (Legacy O) 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 Sep 15, 2000 )

Common NameCanada thistle
SpeciesCirsium arvense
GroupAuxin Mimics HRAC Group 4 (Legacy O)
HerbicidesMCPA
LocationSweden
Year1979
Situation(s)Cropland
Contributors - (Alphabetically) 
Edit this Case  |  Add New Case of Resistance  |  Add Note

NOTES ABOUT THIS BIOTYPE

GENERAL

Fogelfors, H. 1979. "Changes in the Flora of Farmland" Swed. Univ. Agric. Sci. Dept, Ecol. Environ. Res. Rep. No. 5, Uppsala. pp 66.

Edit this Note  |  Add New Note
 

ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Canada thistle biotype with this Canada thistle biotype have been used to confirm resistance. For further information on the tests conducted please contact the local weed scientists that provided this information.
 
Genetics

Genetic studies on HRAC Group 4 resistant Canada thistle 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 4 (Legacy O) resistant Canada thistle from Sweden please update the database.
 
Edit Case  |  Add Note  |  Add Article  |  Add New Case  |  

CONTRIBUTING WEED SCIENTISTS


ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Sweden have been instrumental in providing you this information. 
Herbicide Resistant Canada thistle Globally
(Cirsium arvense)
Herbicide Resistant Canada thistle Globally
(Cirsium arvense)
Drag a column header and drop it here to group by that column
Herbicide Resistant Canada thistle Globally
(Cirsium arvense)
#CountryFirstYearSituationActive IngredientsSite of Action
1 HungaryHungary 1985 Pastures 2,4-D, and MCPA 20 Auxin Mimics ( HRAC Group 4 (Legacy O)
55Cirsium arvenseCanada thistle306
2 SwedenSweden 1979 Cropland MCPA 40 Auxin Mimics ( HRAC Group 4 (Legacy O)
55Cirsium arvenseCanada thistle395
Literature about Similar Cases

Page size:
select
Page: of 6
Items 1 to 5 of 27

Page size:
select
Page: of 6
Items 1 to 5 of 27

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.  Sunday, November 3, 2024 .  Available  www.weedscience.org Copyright © 1993- 2024 WeedScience.org All rights reserved. Fair use of this material is encouraged. Proper citation is requested.