International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
(Ranunculus acris)

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

New Zealand
Tall Buttercup (Ranunculus acris) is a dicot weed in the Ranunculaceae family.  In New Zealand this weed first evolved resistance to Group 2 (Legacy B) herbicides in 2010 and infests Pastures.   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 flumetsulam, and thifensulfuron-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 Nov 17, 2016 )

Common NameTall Buttercup
SpeciesRanunculus acris
GroupInhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicidesflumetsulam, and thifensulfuron-methyl
LocationNew Zealand
Contributors - (Alphabetically)Kerry Harrington 
Edit this Case  |  Add New Case of Resistance  |  Add Note


Confirmation Tests

Greenhouse trials comparing a known susceptible Tall Buttercup biotype with this Tall Buttercup 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 Tall Buttercup 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 Tall Buttercup from New Zealand please update the database.
Edit Case  |  Add Note  |  Add Article  |  Add New Case  |  Help


Massey University
624 Betts Rd
Palmerston North
New Zealand
Email Kerry Harrington


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in New Zealand have been instrumental in providing you this information. Particular thanks is given to Kerry Harrington for providing detailed information.
Herbicide Resistant Tall Buttercup Globally
(Ranunculus acris)
Herbicide Resistant Tall Buttercup Globally
(Ranunculus acris)
Drag a column header and drop it here to group by that column
Herbicide Resistant Tall Buttercup Globally
(Ranunculus acris)
#CountryFirstYearSituationActive IngredientsSite of Action
1 New ZealandNew Zealand 1988 Pastures MCPA 30 Auxin Mimics (O/4)
140Ranunculus acrisTall Buttercup159
2 New ZealandNew Zealand 2010 Pastures flumetsulam, and thifensulfuron-methyl 30 Inhibition of Acetolactate Synthase (B/2)
140Ranunculus acrisTall Buttercup5732
3 New ZealandNew Zealand 2010 Pastures flumetsulam, MCPA, and thifensulfuron-methyl 30 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Auxin Mimics (O/4)
140Ranunculus acrisTall Buttercup14057
Literature about Similar Cases

Page size:
Page: of 2
Items 1 to 5 of 9

Page size:
Page: of 2
Items 1 to 5 of 9
PERMISSION MUST BE OBTAINED FIRST if you intend to base a significant portion of a scientific paper on data derived from this site.
Cite this site as: Heap, I.  The International Survey of Herbicide Resistant Weeds.  Online.  Internet.  Thursday, August 18, 2022 .  Available
Copyright © 1993- 2022 All rights reserved. Fair use of this material is encouraged. Proper citation is requested.