INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

MULTIPLE RESISTANT MARSHWEED
(Limnophila erecta)

Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Auxin Mimics HRAC Group 4 (Legacy O)

Malaysia
INTRODUCTION MARSHWEED
Marshweed (Limnophila erecta) is a dicot weed in the Scrophulariaceae family.  In Malaysia this weed first evolved multiple resistance (to 2 herbicide sites of action) in 2002 and infests Rice.  Multiple resistance has evolved to herbicides in the Groups 2 (Legacy B), and Auxin Mimics HRAC Group 4 (Legacy O).  These particular biotypes are known to have resistance to 2,4-D, bensulfuron-methyl, cinosulfuron, mesosulfuron-methyl, and pyrazosulfuron-ethyl and they may be cross-resistant to other herbicides in the Groups 2 (Legacy B), and Auxin Mimics HRAC Group 4 (Legacy O).

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 Feb 02, 2011 )

Common NameMarshweed
SpeciesLimnophila erecta
GroupInhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

Auxin Mimics HRAC Group 4 (Legacy O)
Herbicides2,4-D, bensulfuron-methyl, cinosulfuron, mesosulfuron-methyl, and pyrazosulfuron-ethyl
LocationMalaysia
Year2002
Situation(s)Rice
Contributors - (Alphabetically)M. Azmi 
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NOTES ABOUT THIS BIOTYPE

CROSS RESISTANCE

Azmi Man
Azmi, M. and Baki, BB (2003). Weed species diversity and management practices in the Sekinchan Farm Block, Selangor's South West Project - a highly productive rice area in Malaysia. Proc. 1 19th APWSS Conference, 17-21 March, Manila Philipines, p. 174-184.

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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Marshweed biotype with this Marshweed 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, 4 resistant Marshweed 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 multiple resistant Marshweed from Malaysia please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

M. AZMI
Malaysian Agricultural Rice Research Institute
108 Sirius Place
Bertam Kepala Betas, 13200, Penang
Malaysia

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Malaysia have been instrumental in providing you this information. Particular thanks is given to M. Azmi for providing detailed information.
Herbicide Resistant Marshweed Globally
(Limnophila erecta)
Herbicide Resistant Marshweed Globally
(Limnophila erecta)
Drag a column header and drop it here to group by that column
Herbicide Resistant Marshweed Globally
(Limnophila erecta)
#CountryFirstYearSituationActive IngredientsSite of Action
1 MalaysiaMalaysia 2002 Rice 2,4-D, bensulfuron-methyl, cinosulfuron, mesosulfuron-methyl, and pyrazosulfuron-ethyl 28 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
Auxin Mimics ( HRAC Group 4 (Legacy O)
 		226Limnophila erectaMarshweed5209
Literature about Similar Cases

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