International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
(Echinochloa oryzoides)

Multiple Resistance: 2 Sites of Action
ACCase inhibitors (A/1)
ALS inhibitors (B/2)

Turkey, Black Sea Trache
Early Watergrass (Echinochloa oryzoides) is a monocot weed in the Poaceae family.  In Turkey this weed first evolved multiple resistance (to 2 herbicide sites of action) in 2009 and infests Rice.  Multiple resistance has evolved to herbicides in the Groups A/1, and B/2.  These particular biotypes are known to have resistance to bispyribac-sodium, cyhalofop-butyl, and penoxsulam and they may be cross-resistant to other herbicides in the Groups A/1, and B/2.

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 Jan 29, 2015 )

Common NameEarly Watergrass
SpeciesEchinochloa oryzoides
GroupACCase inhibitors (A/1)
ALS inhibitors (B/2)
Herbicidesbispyribac-sodium, cyhalofop-butyl, and penoxsulam
LocationTurkey, Black Sea Trache
Contributors - (Alphabetically)Emine Kaya Altop, and Hüsrev Mennan 
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Hüsrev Mennan

Detecting ALS and ACCase herbicide tolerant accession of Echinochloa oryzoides (Ard.) Fritsch. in rice (Oryza sativa L.) fields. 2014. Emine Kaya Altop, Husrev Mennan, Jens Carl Streibig, Unal Budak, Christian Ritz. Crop Protection 65 (2014) 202-206.

 Full Paper in PDF Here:

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Confirmation Tests

Field, Greenhouse, and Laboratory 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.

Genetic studies on Group A, B/1, 2 resistant Early Watergrass indicate that the inheritance is determined by a dominant, nuclear trait.  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 Early Watergrass from Turkey please update the database.
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Weed Scientist
Ondokuz Mayis University
Department Of Plant Protection
Faculty of Agriculture
Samsun, 55139, Kurupelit/Samsun
Email Emine Kaya Altop
Prof. Dr.
University Of Ondokuzmayýs
Department Of Plant Protection
Samsun, 55319, Kurupelit/Samsun
Email Hüsrev Mennan


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Turkey have been instrumental in providing you this information. Particular thanks is given to Emine Kaya Altop, and Hüsrev Mennan 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 TurkeyTurkey 2009 Rice bispyribac-sodium, cyhalofop-butyl, and penoxsulam 71 Multiple Resistance: 2 Sites of Action
ACCase inhibitors (A/1)
ALS inhibitors (B/2)
261Echinochloa oryzoidesEarly Watergrass5530
2 United States (California) United StatesCalifornia2000 Rice molinate, and thiobencarb = benthiocarb 45 Lipid Inhibitors (N/8)
261Echinochloa oryzoidesEarly Watergrass5492
Literature about Similar Cases

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