INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 9 (LEGACY G) RESISTANT EARLY WATERGRASS
(Echinochloa oryzoides)


Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)

Argentina, Santa Fe
INTRODUCTION EARLY WATERGRASS
Early Watergrass (Echinochloa oryzoides) is a monocot weed in the Poaceae family.  In Argentina this weed first evolved resistance to Group 9 (Legacy G) herbicides in 2016 and infests Corn (maize), Rice, Roadsides, and Soybean.   Group 9 (Legacy G) herbicides are known as Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (Inhibition of EPSP synthase).  Research has shown that these particular biotypes are resistant to glyphosate and they may be cross-resistant to other Group 9 (Legacy G) 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 May 09, 2023 )

Common NameEarly Watergrass
SpeciesEchinochloa oryzoides
GroupInhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
Herbicidesglyphosate
LocationArgentina, Santa Fe
Year2016
Situation(s)Corn (maize), Rice, Roadsides, and Soybean
Contributors - (Alphabetically)Eduardo Cortés, Rafael De Prado, and Ignacio Dellaferrera 
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NOTES ABOUT THIS BIOTYPE

GENERAL

Ignacio Dellaferrera

Cortés, E.; Schneider, A.; Panigo, E.; Perreta, M.; De Prado, R.; Dellaferrera, I. First Report of Resistance to Glyphosate in Several Species of the Genus Echinochloa in Argentina. Agronomy 2023, 13, 1219. https://doi.org/10.3390/agronomy 13051219

Abstract: The genus Echinochloa consists of about 33 species worldwide; some of these are weeds that are very difficult to control in Argentina, and only E. colona was reported as resistant to glyphosate. The objective of this work is to determine if one or more populations of E. colona, E. crus-galli, E. oryzoides, and E. chacoensis are resistant to or less susceptible to glyphosate. Between 2015 and 2017, seeds of different Echinochloa populations were collected from the provinces of Córdoba, Santa Fe, Buenos Aires, and Entre Ríos, all from fields with a history of at least 10 consecutive years of glyphosate application and complaints from farmers due to failures in control. With these populations, survival, dose–response, and shikimic acid quantification tests were carried out to determine their level of susceptibility to glyphosate. The results obtained allow us to report the first worldwide case of resistance to glyphosate in populations of E. crus-galli, E. oryzoides, and E. chacoensis and expand the information on E. colona.

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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Early Watergrass biotype with this Early Watergrass 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 9 resistant Early Watergrass 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 9 (Legacy G) resistant Early Watergrass from Argentina please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

EDUARDO CORTÉS
Ingeniero Agrónomo
Asesor e investigador
Castagnino 2041
San Francisco, 2400, Córdoba
Argentina
Email Eduardo Cortés
RAFAEL DE PRADO
Ingeniero Agrónomo
Universidad De Cordoba
Qvimica Agricola Y Edafologa
E T S Ingenieros Agronomos
PO Box 119
Cordoba, E-14080, Andalusia
Spain
Email Rafael De Prado
IGNACIO DELLAFERRERA
Researcher
Universidad Nacional del Litoral
Qvimica Agricola Y Edafologa
E T S Ingenieros Agronomos
French 759
Esperanza, 3080, Santa Fe
Argentina
Email Ignacio Dellaferrera

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Argentina have been instrumental in providing you this information. Particular thanks is given to Eduardo Cortés, Rafael De Prado, and Ignacio Dellaferrera for providing detailed information.
Herbicide Resistant Early Watergrass Globally
(Echinochloa oryzoides)
Herbicide Resistant Early Watergrass Globally
(Echinochloa oryzoides)
Drag a column header and drop it here to group by that column
Herbicide Resistant Early Watergrass Globally
(Echinochloa oryzoides)
#CountryFirstYearSituationActive IngredientsSite of Action
1 ArgentinaArgentina 2016 Corn (maize), Rice, Roadsides, and Soybean glyphosate 48 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase ( HRAC Group 9 (Legacy G)
261Echinochloa oryzoidesEarly Watergrass25261
2 TurkeyTurkey 2009 Rice bispyribac-sodium, cyhalofop-butyl, and penoxsulam 71 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase ( HRAC Group 1 (Legacy A)
Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
261Echinochloa oryzoidesEarly Watergrass5530
3 United States (California) United StatesCalifornia2000 Rice molinate, and thiobencarb/benthiocarb 45 Very Long-Chain Fatty Acid Synthesis inhibitors ( HRAC Group 15 (Legacy K3 N)
261Echinochloa oryzoidesEarly Watergrass5492
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