International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP O/4 RESISTANT COMMON HEMPNETTLE
(Galeopsis tetrahit)


Synthetic Auxins (O/4)

Canada, Alberta
INTRODUCTION COMMON HEMPNETTLE
Common Hempnettle (Galeopsis tetrahit) is a dicot weed in the Lamiaceae family.  In Alberta this weed first evolved resistance to Group O/4 herbicides in 1998 and infests Cereals, Cropland, Spring Barley, and Wheat.   Group O/4 herbicides are known as Synthetic Auxins (Synthetic auxins (action like indoleacetic acid)).  Research has shown that these particular biotypes are resistant to dicamba, fluroxypyr, and MCPA and they may be cross-resistant to other Group O/4 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 Feb 28, 2005 )

Common NameCommon Hempnettle
SpeciesGaleopsis tetrahit
GroupSynthetic Auxins (O/4)
Herbicidesdicamba, fluroxypyr, and MCPA
LocationCanada, Alberta
Year1998
Situation(s)Cereals, Cropland, Spring Barley, and Wheat
Contributors - (Alphabetically)Lyle Friesen, Chris Hall, John O'Donovan, and Tsafrir Weinberg 
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NOTES ABOUT THIS BIOTYPE

AREAS FOUND

John O'Donovan
Lacombe, Alberta, Canada

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ACADEMIC ASPECTS

Confirmation Tests

Field, and Greenhouse trials comparing a known susceptible Common Hempnettle biotype with this Common Hempnettle 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 O/4 resistant Common Hempnettle 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 O/4 resistant Common Hempnettle from Alberta please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

LYLE FRIESEN
University Of Manitoba
Agriculture Bldg
Rua Hugo Cabral 1065 Apto 301
Winnipeg, R3T 2N2, Manitoba
Canada
Email Lyle Friesen
CHRIS HALL
University Of Guelph
Department Of Environmental Biology
Dept. Producao Vegetal
Caixa Postal 09, Av. Padua Dias 11
Guelph, N1G 2W1, Ontario
Canada
Email Chris Hall
JOHN O'DONOVAN
Agriculture And Agri-Food Canada
Department Of Environmental Biology
Universidad Nacional De Mar Del Plata
Ruta Nacional 226, Km 73.5,
Beaverlodge, T0H 0C0, Alberta
Canada
Email John O'Donovan
TSAFRIR WEINBERG
Ph. D. Student
University Of Guelph
Depart. Of Environmental Biology
108 Waters Hall
Guelph, N1G 2W1, Ontario
Canada
Email Tsafrir Weinberg

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Alberta have been instrumental in providing you this information. Particular thanks is given to Lyle Friesen, Chris Hall, John O'Donovan, and Tsafrir Weinberg for providing detailed information.
Herbicide Resistant Common Hempnettle Globally
(Galeopsis tetrahit)
Herbicide Resistant Common Hempnettle Globally
(Galeopsis tetrahit)
Drag a column header and drop it here to group by that column
Herbicide Resistant Common Hempnettle Globally
(Galeopsis tetrahit)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Canada (Manitoba) CanadaManitoba1995 Cereals, and Wheat metsulfuron-methyl 7 ALS inhibitors (B/2)
91Galeopsis tetrahitCommon Hempnettle476
2 Canada (Alberta) CanadaAlberta1998 Cereals, Cropland, Spring Barley, and Wheat dicamba, fluroxypyr, and MCPA 7 Synthetic Auxins (O/4)
91Galeopsis tetrahitCommon Hempnettle1154
3 Canada (Alberta) CanadaAlberta2006 Cereals thifensulfuron-methyl, and tribenuron-methyl 7 ALS inhibitors (B/2)
91Galeopsis tetrahitCommon Hempnettle5320
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Cite this site as: Heap, I.  The International Survey of Herbicide Resistant Weeds.  Online.  Internet.  Friday, April 28, 2017 .  Available  www.weedscience.org
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