International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP O/4 RESISTANT YELLOW STARTHISTLE
(Centaurea solstitialis)


Synthetic Auxins (O/4)

United States, Washington
INTRODUCTION YELLOW STARTHISTLE
Yellow Starthistle (Centaurea solstitialis) is a dicot weed in the Asteraceae family.  In Washington this weed first evolved resistance to Group O/4 herbicides in 1988 and infests Roadsides.   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 picloram 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 Sep 15, 2000 )

Common NameYellow Starthistle
SpeciesCentaurea solstitialis
GroupSynthetic Auxins (O/4)
Herbicidespicloram
LocationUnited States, Washington
Year1988
Situation(s)Roadsides
Contributors - (Alphabetically)Steven Seefeldt 
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NOTES ABOUT THIS BIOTYPE

GENERAL

Steve Seefeldt is now working on resistant weeds in NewZealand.

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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse, and Laboratory trials comparing a known susceptible Yellow Starthistle biotype with this Yellow Starthistle 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 Yellow Starthistle 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 Yellow Starthistle from Washington please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

STEVEN SEEFELDT
Ruakura Agricultural Research Centre
Agresearch
Universidad Nacional La Plata
Casilla De Correo 31, Cátedra De Cereales
Hamilton
New Zealand
Email Steven Seefeldt

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Washington have been instrumental in providing you this information. Particular thanks is given to Steven Seefeldt for providing detailed information.
Herbicide Resistant Yellow Starthistle Globally
(Centaurea solstitialis)
Herbicide Resistant Yellow Starthistle Globally
(Centaurea solstitialis)
Drag a column header and drop it here to group by that column
Herbicide Resistant Yellow Starthistle Globally
(Centaurea solstitialis)
#CountryFirstYearSituationActive IngredientsSite of Action
1 United States (Washington) United StatesWashington1988 Roadsides picloram 45 Synthetic Auxins (O/4)
44Centaurea solstitialisYellow Starthistle515
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Cite this site as: Heap, I.  The International Survey of Herbicide Resistant Weeds.  Online.  Internet.  Monday, October 14, 2019 .  Available  www.weedscience.org
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