International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
(Polygonum hydropiper)

Photosystem II- Serine 264 Binders (C1/5)

Marshpepper Smartweed (Polygonum hydropiper) is a dicot weed in the Polygonaceae family.  In France this weed first evolved resistance to Group C1/5 herbicides in 1989 and infests Corn (maize), and Cropland.   Group C1/5 herbicides are known as Photosystem II- 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 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.

If we do not have a picture for this weed, or you can provide a better picture (scan, digital camera etc) please please e-mail it to us.

QUIK STATS (last updated Sep 15, 2000 )

Common NameMarshpepper Smartweed
SpeciesPolygonum hydropiper
GroupPhotosystem II- Serine 264 Binders (C1/5)
Situation(s)Corn (maize), and Cropland
Contributors - (Alphabetically)Jacques Gasquez 
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Confirmation Tests

Greenhouse trials comparing a known susceptible Marshpepper Smartweed biotype with this Marshpepper Smartweed biotype have been used to confirm resistance. For further information on the tests conducted please contact the local weed scientists that provided this information.

Genetic studies on Group C1/5 resistant Marshpepper Smartweed 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 Marshpepper Smartweed from France.
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Laboratoire De Malherbologie
702 Hickory Ct
Dijon, 21034, Cedex
Email Jacques Gasquez


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in France have been instrumental in providing you this information. Particular thanks is given to Jacques Gasquez for providing detailed information.
Herbicide Resistant Marshpepper Smartweed Globally
(Polygonum hydropiper)
Herbicide Resistant Marshpepper Smartweed Globally
(Polygonum hydropiper)
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Herbicide Resistant Marshpepper Smartweed Globally
(Polygonum hydropiper)
#CountryFirstYearSituationActive IngredientsSite of Action
1 FranceFrance 1989 Corn (maize), and Cropland atrazine 17 Photosystem II- Serine 264 Binders (C1/5)
133Polygonum hydropiperMarshpepper Smartweed465
Literature about Similar Cases

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