International Survey of Herbicide-Resistant Weeds

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(Rumex dentatus)

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

Toothed Dock (Rumex dentatus) is a dicot weed in the Polygonaceae family.  In India this weed first evolved resistance to Group 2 (Legacy B) herbicides in 2014 and infests Wheat.   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 florasulam, iodosulfuron-methyl-Na, mesosulfuron-methyl, and pyroxsulam 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.

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QUIK STATS (last updated Jan 20, 2015 )

Common NameToothed Dock
SpeciesRumex dentatus
GroupInhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicidesflorasulam, iodosulfuron-methyl-Na, mesosulfuron-methyl, and pyroxsulam
Contributors - (Alphabetically)Rajender Chhokar 
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Rajender Chhokar

Metsulfuron resistance in Rumex dentatus

Rumex dentatus (Toothed dock) is a major broadleaf weed of Rabi season and is a serious problem of irrigated wheat particularly of rice-wheat system. This weed is highly competitive and besides reducing the yield also interferes with combine harvesting. Rumex dentatus is highly sensitive to metsulfuron and this herbicide is providing effective control of this weed for the last 15 years in wheat in India. However, during 2013 in pot and field studies it was observed that one of the population of Rumex dentatus has evolved metsulfuron resistance (ALS inhibition). It has shown the cross-resistance to mesosulfuron + Iodosulfuron, pyroxsulam, halauxifen + florasulam. For its control, carfentrazone, 2,4-D amine, pendimethalin and isoproturon were found effective. 

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Confirmation Tests

Greenhouse, and Laboratory trials comparing a known susceptible Toothed Dock biotype with this Toothed Dock 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 Toothed Dock 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 Toothed Dock from India please update the database.
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Senior Scientist
Directorate of Wheat Research
Resource Management Programme
Aggarsain Marg
Karnal, 132001, Haryana
Email Rajender Chhokar


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in India have been instrumental in providing you this information. Particular thanks is given to Rajender Chhokar for providing detailed information.
Herbicide Resistant Toothed Dock Globally
(Rumex dentatus)
Herbicide Resistant Toothed Dock Globally
(Rumex dentatus)
Drag a column header and drop it here to group by that column
Herbicide Resistant Toothed Dock Globally
(Rumex dentatus)
#CountryFirstYearSituationActive IngredientsSite of Action
1 IndiaIndia 2014 Wheat florasulam, iodosulfuron-methyl-Na, mesosulfuron-methyl, and pyroxsulam 21 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
320Rumex dentatusToothed Dock10949
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