INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

MULTIPLE RESISTANT SOURGRASS
(Digitaria insularis)


Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)

Brazil, Mato Grosso and Mato Grosso do Sul State
INTRODUCTION SOURGRASS
Sourgrass (Digitaria insularis) is a monocot weed in the Poaceae family.  In Brazil this weed first evolved multiple resistance (to 2 herbicide sites of action) in 2020 and infests Soybean.  Multiple resistance has evolved to herbicides in the Groups 1 (Legacy A), and Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G).  These particular biotypes are known to have resistance to fenoxaprop-ethyl, glyphosate, and haloxyfop-methyl and they may be cross-resistant to other herbicides in the Groups 1 (Legacy A), and Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G).

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 Feb 04, 2021 )

Common NameSourgrass
SpeciesDigitaria insularis
GroupInhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)

Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
Herbicidesfenoxaprop-ethyl, glyphosate, and haloxyfop-methyl
LocationBrazil, Mato Grosso and Mato Grosso do Sul State
Year2020
Situation(s)Soybean
Contributors - (Alphabetically)Pedro Christoffoleti, Thiago De Oliveira, and Marcel Sereguin Cabral de Melo 
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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse, and Laboratory trials comparing a known susceptible Sourgrass biotype with this Sourgrass 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 1, 9 resistant Sourgrass 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 Sourgrass from Brazil please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

PEDRO CHRISTOFFOLETI
Associate Professor III
Universidade de Sao Paulo
Crop Science Department
ESALQ - USP - LPV - Av. Padua Dias 11 - C. Postal 09
Piracicaba, 13418-900, São Paulo
Brazil
Email Pedro Christoffoleti
Web   : Web Site Link
THIAGO DE OLIVEIRA
Indication Project Senior Manager
BASF
R&D
Avenida Nacoes Unidas
Rochaverá, 04794-000, Sao Paulo
Brazil
Email Thiago De Oliveira
Web   : Web Site Link
MARCEL SEREGUIN CABRAL DE MELO
Weed Resistance Monitoring Specialist
Bayer
Plant growth
5005, Dr. Roberto Moreira avenue
Bairro Recanto dos pássaros, Setor EAE
Paulínia, 13148-914, Sao Paulo
Brazil
Email Marcel Sereguin Cabral de Melo
Web   : Web Site Link

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Brazil have been instrumental in providing you this information. Particular thanks is given to Pedro Christoffoleti, Thiago De Oliveira, and Marcel Sereguin Cabral de Melo for providing detailed information.
Herbicide Resistant Sourgrass Globally
(Digitaria insularis)
Herbicide Resistant Sourgrass Globally
(Digitaria insularis)
Drag a column header and drop it here to group by that column
Herbicide Resistant Sourgrass Globally
(Digitaria insularis)
#CountryFirstYearSituationActive IngredientsSite of Action
1 ArgentinaArgentina 2014 Soybean glyphosate 48 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase ( HRAC Group 9 (Legacy G)
239Digitaria insularisSourgrass13049
2 BrazilBrazil 2008 Corn (maize), and Soybean glyphosate 5 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase ( HRAC Group 9 (Legacy G)
239Digitaria insularisSourgrass5350
3 BrazilBrazil 2016 Soybean fenoxaprop-ethyl, and haloxyfop-methyl 5 Inhibition of Acetyl CoA Carboxylase ( HRAC Group 1 (Legacy A)
239Digitaria insularisSourgrass13043
4 BrazilBrazil 2020 Soybean fenoxaprop-ethyl, glyphosate, and haloxyfop-methyl 5 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase ( HRAC Group 1 (Legacy A)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase ( HRAC Group 9 (Legacy G)
239Digitaria insularisSourgrass19212
5 ParaguayParaguay 2005 Corn (maize), Cotton, Soybean, and Sunflower glyphosate 46 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase ( HRAC Group 9 (Legacy G)
239Digitaria insularisSourgrass5351
6 ParaguayParaguay 2020 Soybean clethodim, glyphosate, and haloxyfop-methyl 46 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase ( HRAC Group 1 (Legacy A)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase ( HRAC Group 9 (Legacy G)
239Digitaria insularisSourgrass20223
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