International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP C2/7 RESISTANT DOWNY BROME (CHEATGRASS)
(Bromus tectorum)


PSII inhibitor (Ureas and amides) (C2/7)

Spain
INTRODUCTION DOWNY BROME (CHEATGRASS)
Downy Brome (Cheatgrass) (Bromus tectorum) is a monocot weed in the Poaceae family.  In Spain this weed first evolved resistance to Group C2/7 herbicides in 1990 and infests Wheat.   Group C2/7 herbicides are known as PSII inhibitor (Ureas and amides) (Inhibition of photosynthesis at photosystem II).  Research has shown that these particular biotypes are resistant to chlorotoluron and they may be cross-resistant to other Group C2/7 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 Nov 18, 2000 )

Common NameDowny Brome (Cheatgrass)
SpeciesBromus tectorum
GroupPSII inhibitor (Ureas and amides) (C2/7)
Herbicideschlorotoluron
LocationSpain
Year1990
Situation(s)Wheat
Contributors - (Alphabetically)Rafael De Prado 
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NOTES ABOUT THIS BIOTYPE

AREAS FOUND

Rafael De Prado
Pueblonueuo (Cordoba)

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GENERAL

Rafael De Prado
Enhanced detoxification

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ACADEMIC ASPECTS

Confirmation Tests

Field, Greenhouse, and Laboratory trials comparing a known susceptible Downy Brome (Cheatgrass) biotype with this Downy Brome (Cheatgrass) 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 Group C2/7 resistant Downy Brome (Cheatgrass) 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

Studies on the mechanism of resistance of Group C2/7 resistant Downy Brome (Cheatgrass) from Spain indicate that resistance is due to enhanced metabolism.  There may be a note below or an article discussing the mechanism of resistance in the Fact Sheets and Other Literature
 
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 C2/7 resistant Downy Brome (Cheatgrass) from Spain please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

RAFAEL DE PRADO
Universidad De Cordoba
Qvimica Agricola Y Edafologa
E T S Ingenieros Agronomos
PO Box 119
Cordoba, E-14080, Andalusia
Spain
Email Rafael De Prado

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Spain have been instrumental in providing you this information. Particular thanks is given to Rafael De Prado for providing detailed information.
Herbicide Resistant Downy Brome (Cheatgrass) Globally
(Bromus tectorum)
Herbicide Resistant Downy Brome (Cheatgrass) Globally
(Bromus tectorum)
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Herbicide Resistant Downy Brome (Cheatgrass) Globally
(Bromus tectorum)
#CountryFirstYearSituationActive IngredientsSite of Action
1 FranceFrance 1981 Corn (maize) atrazine 17 Photosystem II inhibitors (C1/5)
40Bromus tectorumDowny Brome (Cheatgrass)457
2 SpainSpain 1990 Wheat chlorotoluron 38 PSII inhibitor (Ureas and amides) (C2/7)
40Bromus tectorumDowny Brome (Cheatgrass)190
3 SpainSpain 1990 Orchards simazine 38 Photosystem II inhibitors (C1/5)
40Bromus tectorumDowny Brome (Cheatgrass)191
4 United States (Oregon) United StatesOregon1997 Kentucky bluegrass imazamox, primisulfuron-methyl, and sulfosulfuron 45 ALS inhibitors (B/2)
40Bromus tectorumDowny Brome (Cheatgrass)1112
5 United States (Oregon) United StatesOregon2005 Grass seed clethodim, fluazifop-P-butyl, quizalofop-P-ethyl, and sethoxydim 45 ACCase inhibitors (A/1)
40Bromus tectorumDowny Brome (Cheatgrass)5375
6 United States (Montana) United StatesMontana2016 Wheat imazamox, procarbazone-sodium, and pyroxsulam 45 ALS inhibitors (B/2)
40Bromus tectorumDowny Brome (Cheatgrass)15071
Literature about Similar Cases

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