International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
HRAC GROUP 2 (LEGACY B) RESISTANT EARED REDSTEM
(Ammannia auriculata)

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

United States, California
INTRODUCTION EARED REDSTEM
Eared Redstem (Ammannia auriculata) is a dicot weed in the Lythraceae family.  In California this weed first evolved resistance to Group 2 (Legacy B) herbicides in 1997 and infests Rice.   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 bensulfuron-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.

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QUIK STATS (last updated Sep 15, 2000 )

Common NameEared Redstem
SpeciesAmmannia auriculata
GroupInhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicidesbensulfuron-methyl
LocationUnited States, California
Year1997
Situation(s)Rice
Contributors - (Alphabetically)Jim Hill 
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ACADEMIC ASPECTS

Confirmation Tests

Field, and Greenhouse trials comparing a known susceptible Eared Redstem biotype with this Eared Redstem 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 2 resistant Eared Redstem 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 Eared Redstem from California please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

JIM HILL
CE Specialist
University Of California
Agriculture and Natural Resources
One Shields Avenue
177 Hunt Hall
Davis, 95616, California
United States
Email Jim Hill
Web   : Web Site Link

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in California have been instrumental in providing you this information. Particular thanks is given to Jim Hill for providing detailed information.
Herbicide Resistant Eared Redstem Globally
(Ammannia auriculata)
Herbicide Resistant Eared Redstem Globally
(Ammannia auriculata)
Drag a column header and drop it here to group by that column
Herbicide Resistant Eared Redstem Globally
(Ammannia auriculata)
#CountryFirstYearSituationActive IngredientsSite of Action
1 ChinaChina 2023 Rice bensulfuron-methyl 9 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
 		183Ammannia auriculataEared Redstem27280
2 United States (California) United StatesCalifornia1997 Rice bensulfuron-methyl 45 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
 		183Ammannia auriculataEared Redstem1098
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