International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP C2/7 RESISTANT POWELL AMARANTH
(Amaranthus powellii)


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

Canada, Quebec
INTRODUCTION POWELL AMARANTH
Powell Amaranth (Amaranthus powellii) is a dicot weed in the Amaranthaceae family.  In Quebec this weed first evolved resistance to Group C2/7 herbicides in 2012 and infests Carrots.   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 linuron 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 Jan 27, 2018 )

Common NamePowell Amaranth
SpeciesAmaranthus powellii
GroupPSII inhibitor (Ureas and amides) (C2/7)
Herbicideslinuron
LocationCanada, Quebec
Year2012
Situation(s)Carrots
Contributors - (Alphabetically)Francois Tardif 
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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 C2/7 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 C2/7 resistant Powell Amaranth from Quebec please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

FRANCOIS TARDIF
Associate Professor
University Of Guelph
Department Of Plant Agriculture
2055 Radatz Ave
Guelph, N1G 2W1, Ontario
Canada
Email Francois Tardif
Web   : Web Site Link

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Quebec have been instrumental in providing you this information. Particular thanks is given to Francois Tardif 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 Canada (Quebec) CanadaQuebec2012 Carrots linuron 7 PSII inhibitor (Ureas and amides) (C2/7)
15Amaranthus powelliiPowell Amaranth17123
7 Canada (Quebec) CanadaQuebec2012 Soybean imazethapyr 7 ALS inhibitors (B/2)
15Amaranthus powelliiPowell Amaranth17124
8 Czech RepublicCzech Republic 1989 Orchards atrazine, cyanazine, prometryn, simazine, and terbutryn 12 Photosystem II inhibitors (C1/5)
15Amaranthus powelliiPowell Amaranth78
9 FranceFrance 1982 Corn (maize) atrazine 17 Photosystem II inhibitors (C1/5)
15Amaranthus powelliiPowell Amaranth452
10 SwitzerlandSwitzerland 1986 Corn (maize) atrazine 41 Photosystem II inhibitors (C1/5)
15Amaranthus powelliiPowell Amaranth197
11 United States (Washington) United StatesWashington1992 Mint terbacil 45 Photosystem II inhibitors (C1/5)
15Amaranthus powelliiPowell Amaranth331
12 United States (Ohio) United StatesOhio1996 Soybean imazaquin 45 ALS inhibitors (B/2)
15Amaranthus powelliiPowell Amaranth1100
13 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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