International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
HRAC GROUP 5 (LEGACY C1 C2) RESISTANT HALBERDLEAF ORACH
(Atriplex patula)


PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)

United States, Michigan
INTRODUCTION HALBERDLEAF ORACH
Halberdleaf Orach (Atriplex patula) is a dicot weed in the Chenopodiaceae family.  In Michigan this weed first evolved resistance to Group 5 (Legacy C1 C2) herbicides in 2003 and infests Corn (maize).   Group 5 (Legacy C1 C2) herbicides are known as PSII inhibitors - Serine 264 Binders (Inhbition of Photosynthesis at PSll - Serine 264 Binders ).  Research has shown that these particular biotypes are resistant to atrazine and they may be cross-resistant to other Group 5 (Legacy C1 C2) 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 Mar 05, 2007 )

Common NameHalberdleaf Orach
SpeciesAtriplex patula
GroupPSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
Herbicidesatrazine
LocationUnited States, Michigan
Year2003
Situation(s)Corn (maize)
Contributors - (Alphabetically)Steven Gower 
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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse 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 HRAC Group 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

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 5 (Legacy C1 C2) resistant Halberdleaf Orach from Michigan please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

STEVEN GOWER
Former Weed Science Diagnostician (Now with Monsanto)
Michigan State University
Diagnostic Services
578 Wilson Rd.
East Lansing, 48824, Michigan
United States
Email Steven Gower

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Michigan have been instrumental in providing you this information. Particular thanks is given to Steven Gower 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 PSII inhibitors - Serine 264 Binders (C1 C2/5)
26Atriplex patulaHalberdleaf Orach11017
2 GermanyGermany 1980 Corn (maize) atrazine 18 PSII inhibitors - Serine 264 Binders (C1 C2/5)
26Atriplex patulaHalberdleaf Orach442
3 United States (Michigan) United StatesMichigan2003 Corn (maize) atrazine 45 PSII inhibitors - Serine 264 Binders (C1 C2/5)
26Atriplex patulaHalberdleaf Orach5291
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Cite this site as: Heap, I.  The International Survey of Herbicide Resistant Weeds.  Online.  Internet.  Wednesday, October 27, 2021 .  Available  www.weedscience.org
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