International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP B/2 RESISTANT SPINY SOWTHISTLE
(Sonchus asper)


ALS inhibitors (B/2)

United States, Washington
INTRODUCTION SPINY SOWTHISTLE
Spiny Sowthistle (Sonchus asper) is a dicot weed in the Asteraceae family.  In Washington this weed first evolved resistance to Group B/2 herbicides in 2000 and infests Lentils, and Wheat.   Group B/2 herbicides are known as ALS inhibitors (Inhibition of acetolactate synthase ALS (acetohydroxyacid synthase AHAS)).  Research has shown that these particular biotypes are resistant to imazamox, and thifensulfuron-methyl and they may be cross-resistant to other Group B/2 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 Jun 16, 2003 )

Common NameSpiny Sowthistle
SpeciesSonchus asper
GroupALS inhibitors (B/2)
Herbicidesimazamox, and thifensulfuron-methyl
LocationUnited States, Washington
Year2000
Situation(s)Lentils, and Wheat
Contributors - (Alphabetically)Kee-Woong Park 
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ACADEMIC ASPECTS

Confirmation Tests

Field, Greenhouse, and Laboratory trials comparing a known susceptible Spiny Sowthistle biotype with this Spiny Sowthistle 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 B/2 resistant Spiny Sowthistle 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

Studies on the mechanism of resistance of Group B/2 resistant Spiny Sowthistle from Washington indicate that resistance is due to an altered target site.  There may be a note below or an article discussing the mechanism of resistance in the Fact Sheets and Other Literature
 
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 B/2 resistant Spiny Sowthistle from Washington please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

KEE-WOONG PARK
Professor
Chungnam National University
Department Of Crop Science
99 Daehak-ro
Yuseong-gu
Daejeon, 305-764
South Korea
Email Kee-Woong Park

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 Kee-Woong Park for providing detailed information.
Herbicide Resistant Spiny Sowthistle Globally
(Sonchus asper)
Herbicide Resistant Spiny Sowthistle Globally
(Sonchus asper)
Drag a column header and drop it here to group by that column
Herbicide Resistant Spiny Sowthistle Globally
(Sonchus asper)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Canada (Alberta) CanadaAlberta1996 Pastures, and Spring Barley chlorsulfuron, metsulfuron-methyl, thifensulfuron-methyl, and tribenuron-methyl 7 ALS inhibitors (B/2)
163Sonchus asperSpiny Sowthistle1153
2 FranceFrance 1980 Corn (maize) atrazine 17 Photosystem II inhibitors (C1/5)
163Sonchus asperSpiny Sowthistle473
3 FranceFrance 2015 Chicory rimsulfuron 17 ALS inhibitors (B/2)
163Sonchus asperSpiny Sowthistle14058
4 NorwayNorway 2006 Spring Barley, and Spring wheat iodosulfuron-methyl-sodium, and tribenuron-methyl 31 ALS inhibitors (B/2)
163Sonchus asperSpiny Sowthistle10976
5 United States (Washington) United StatesWashington2000 Lentils, and Wheat imazamox, and thifensulfuron-methyl 45 ALS inhibitors (B/2)
163Sonchus asperSpiny Sowthistle5186
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Cite this site as: Heap, I.  The International Survey of Herbicide Resistant Weeds.  Online.  Internet.  Sunday, September 15, 2019 .  Available  www.weedscience.org
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