International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP B/2 RESISTANT POWELL AMARANTH
(Amaranthus powellii)


ALS inhibitors (B/2)

Canada, Manitoba
INTRODUCTION POWELL AMARANTH
Powell Amaranth (Amaranthus powellii) is a dicot weed in the Amaranthaceae family.  In Manitoba this weed first evolved resistance to Group B/2 herbicides in 2008 and infests Beans, and Wheat.   Group B/2 herbicides are known as ALS inhibitors (Inhibition of acetolactate synthase ALS (acetohydroxyacid synthase AHAS)).  Research has shown that these particular biotypes are resistant to thifensulfuron-methyl, and tribenuron-methyl and they may be cross-resistant to other Group B/2 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 02, 2012 )

Common NamePowell Amaranth
SpeciesAmaranthus powellii
GroupALS inhibitors (B/2)
Herbicidesthifensulfuron-methyl, and tribenuron-methyl
LocationCanada, Manitoba
Year2008
Situation(s)Beans, and Wheat
Contributors - (Alphabetically)Hugh Beckie 
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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Powell Amaranth biotype with this Powell Amaranth 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 B/2 resistant Powell Amaranth 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 B/2 resistant Powell Amaranth from Manitoba please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

HUGH BECKIE
Research Scientist
Agriculture & Agri-Food Canada, Science & Technology Branch
Herbicide-Resistant & Novel-Trait Plants
107 Science Place
Saskatoon, S7N 0X2, Saskatchewan
Canada
Email Hugh Beckie

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Manitoba have been instrumental in providing you this information. Particular thanks is given to Hugh Beckie for providing detailed information.
Herbicide Resistant Powell Amaranth Globally
(Amaranthus powellii)
Herbicide Resistant Powell Amaranth Globally
(Amaranthus powellii)
Drag a column header and drop it here to group by that column
Herbicide Resistant Powell Amaranth Globally
(Amaranthus powellii)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Canada (Ontario) CanadaOntario1977 Corn (maize) atrazine, and metribuzin 7 Photosystem II inhibitors (C1/5)
15Amaranthus powelliiPowell Amaranth1158
2 Canada (Ontario) CanadaOntario1998 Corn (maize), Cropland, and Soybean imazethapyr, and thifensulfuron-methyl 7 ALS inhibitors (B/2)
15Amaranthus powelliiPowell Amaranth1159
3 Canada (Ontario) CanadaOntario1998 Corn (maize), Soybean, and Wheat atrazine, imazethapyr, and metribuzin 7 Multiple Resistance: 2 Sites of Action
ALS inhibitors (B/2)
Photosystem II inhibitors (C1/5)
15Amaranthus powelliiPowell Amaranth5049
4 Canada (Ontario) CanadaOntario1999 Carrots atrazine, linuron, monolinuron, and prometryn 7 Multiple Resistance: 2 Sites of Action
Photosystem II inhibitors (C1/5)
PSII inhibitor (Ureas and amides) (C2/7)
15Amaranthus powelliiPowell Amaranth5048
5 Canada (Manitoba) CanadaManitoba2008 Beans, and Wheat thifensulfuron-methyl, and tribenuron-methyl 7 ALS inhibitors (B/2)
15Amaranthus powelliiPowell Amaranth5631
6 Czech RepublicCzech Republic 1989 Orchards atrazine, cyanazine, prometryn, simazine, and terbutryn 12 Photosystem II inhibitors (C1/5)
15Amaranthus powelliiPowell Amaranth78
7 FranceFrance 1982 Corn (maize) atrazine 17 Photosystem II inhibitors (C1/5)
15Amaranthus powelliiPowell Amaranth452
8 SwitzerlandSwitzerland 1986 Corn (maize) atrazine 41 Photosystem II inhibitors (C1/5)
15Amaranthus powelliiPowell Amaranth197
9 United States (Washington) United StatesWashington1992 Mint terbacil 45 Photosystem II inhibitors (C1/5)
15Amaranthus powelliiPowell Amaranth331
10 United States (Ohio) United StatesOhio1996 Soybean imazaquin 45 ALS inhibitors (B/2)
15Amaranthus powelliiPowell Amaranth1100
11 United States (Michigan) United StatesMichigan2001 Asparagus, and Nurseries atrazine, and diuron 45 Multiple Resistance: 2 Sites of Action
Photosystem II inhibitors (C1/5)
PSII inhibitor (Ureas and amides) (C2/7)
15Amaranthus powelliiPowell Amaranth5176
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