International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP C1/5 RESISTANT PENNSYLVANIA SMARTWEED
(Polygonum pensylvanicum)


Photosystem II inhibitors (C1/5)

United States, Iowa
INTRODUCTION PENNSYLVANIA SMARTWEED
Pennsylvania Smartweed (Polygonum pensylvanicum) is a dicot weed in the Polygonaceae family.  In Iowa this weed first evolved resistance to Group C1/5 herbicides in 1990 and infests Corn (maize).   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 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.

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QUIK STATS (last updated Sep 15, 2000 )

Common NamePennsylvania Smartweed
SpeciesPolygonum pensylvanicum
GroupPhotosystem II inhibitors (C1/5)
Herbicidesatrazine
LocationUnited States, Iowa
Year1990
Situation(s)Corn (maize)
Contributors - (Alphabetically)Jack Dekker (Retired), and Micheal Owen 
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NOTES ABOUT THIS BIOTYPE

AREAS FOUND

Jack Dekker (Retired)
Northeast Iowa

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ACADEMIC ASPECTS

Confirmation Tests

Field, and Laboratory trials comparing a known susceptible Pennsylvania Smartweed biotype with this Pennsylvania 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.
 
Genetics

Genetic studies on Group C1/5 resistant Pennsylvania 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 Pennsylvania Smartweed from Iowa.
 
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CONTRIBUTING WEED SCIENTISTS

JACK DEKKER (RETIRED)
Iowa State University
Agronomy Dept.
6394 Grandview Road
Ames, 50011, Iowa
United States
Email Jack Dekker (Retired)
MICHEAL OWEN
Associate Chair And Professor
Iowa State University
Agronomy Department
3218 Agronomy Hall
Ames, 50011, Iowa
United States
Email Micheal Owen
Web   : Web Site Link

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Iowa have been instrumental in providing you this information. Particular thanks is given to Jack Dekker (Retired), and Micheal Owen for providing detailed information.
Herbicide Resistant Pennsylvania Smartweed Globally
(Polygonum pensylvanicum)
Herbicide Resistant Pennsylvania Smartweed Globally
(Polygonum pensylvanicum)
Drag a column header and drop it here to group by that column
Herbicide Resistant Pennsylvania Smartweed Globally
(Polygonum pensylvanicum)
#CountryFirstYearSituationActive IngredientsSite of Action
1 United States (Iowa) United StatesIowa1990 Corn (maize) atrazine 45 Photosystem II inhibitors (C1/5)
135Polygonum pensylvanicumPennsylvania Smartweed240
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