International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP C1/5 RESISTANT HALBERDLEAF ORACH
(Atriplex patula)


Photosystem II inhibitors (C1/5)

Belgium, Flemish Brabant
INTRODUCTION HALBERDLEAF ORACH
Halberdleaf Orach (Atriplex patula) is a dicot weed in the Chenopodiaceae family.  In Belgium this weed first evolved resistance to Group C1/5 herbicides in 2015 and infests Sugar beets.   Group C1/5 herbicides are known as Photosystem II inhibitors (Inhibition of photosynthesis at photosystem II).  Research has shown that these particular biotypes are resistant to desmedipham, lenacil, metamitron, and phenmedipham and they may be cross-resistant to other Group C1/5 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 04, 2016 )

Common NameHalberdleaf Orach
SpeciesAtriplex patula
GroupPhotosystem II inhibitors (C1/5)
Herbicidesdesmedipham, lenacil, metamitron, and phenmedipham
LocationBelgium, Flemish Brabant
Year2015
Situation(s)Sugar beets
Contributors - (Alphabetically)Sofie Claerhout, and Benny De Cauwer 
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NOTES ABOUT THIS BIOTYPE

GENERAL

Benny De Cauwer
The susceptibility to sugar beet herbicides was examined in pot experiments with 7 doses of each herbicide and 3 replicates. Pot experiments were run twice. Evolved resistance was found in two A. patula populations. These populations were low level (RI <10) to high level (RI >10) cross-resistant to the photosystem II inhibitors (HRAC group C1) metamitron (RI≈6.8-15.6), phenmedipham (RI≈3.0-8.5), desmedipham (RI≈3.0-8.7) and lenacil (RI≈6.6-10.5), and negative cross-resistant (RI≈0.5) to HRAC group K3 herbicide dimethenamide-P. This biotype is found in the Province of Flemish Brabant. This biotype is present in a few sugar beet fields (sugar beet/potato/wheat crop rotation)

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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse, and Laboratory trials comparing a known susceptible Halberdleaf Orach biotype with this Halberdleaf Orach 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 C1/5 resistant Halberdleaf Orach 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

Triazine resistant weeds often exhibit a lower relative fitness when compared to susceptible biotypes.  The most common mutation conferring triazine resistance (Ser 264 to Gly mutation of the psbA gene) also causes a reduction in CO2 fixation, quantum yield, and seed and biomass production.  There is no record in this database referring specifically to fitness studies on Group C1/5 resistant Halberdleaf Orach from Belgium.
 
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CONTRIBUTING WEED SCIENTISTS

SOFIE CLAERHOUT
Weed Science Unit
Ghent University
Department of Plant Production
Faculty of Bioscience Engineering
Coupure Links 653
Gent, 9000, Flemish Region
Belgium
Email Sofie Claerhout
BENNY DE CAUWER
Doctor assistant, Research associate
University of Ghent, faculty of Bioscience-engineering
Dept. Plant Production
Weed Science Unit
Coupure Links 653
9000 Gent, 9000, Flemish Region
Belgium
Email Benny De Cauwer

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Belgium have been instrumental in providing you this information. Particular thanks is given to Sofie Claerhout, and Benny De Cauwer for providing detailed information.
Herbicide Resistant Halberdleaf Orach Globally
(Atriplex patula)
Herbicide Resistant Halberdleaf Orach Globally
(Atriplex patula)
Drag a column header and drop it here to group by that column
Herbicide Resistant Halberdleaf Orach Globally
(Atriplex patula)
#CountryFirstYearSituationActive IngredientsSite of Action
1 BelgiumBelgium 2015 Sugar beets desmedipham, lenacil, metamitron, and phenmedipham 3 Photosystem II inhibitors (C1/5)
26Atriplex patulaHalberdleaf Orach11017
2 GermanyGermany 1980 Corn (maize) atrazine 18 Photosystem II inhibitors (C1/5)
26Atriplex patulaHalberdleaf Orach442
3 United States (Michigan) United StatesMichigan2003 Corn (maize) atrazine 45 Photosystem II inhibitors (C1/5)
26Atriplex patulaHalberdleaf Orach5291
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Cite this site as: Heap, I.  The International Survey of Herbicide Resistant Weeds.  Online.  Internet.  Sunday, April 30, 2017 .  Available  www.weedscience.org
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