International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
(Bidens pilosa)

Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)

Mexico, Gulf of Mexico
Hairy Beggarticks (Bidens pilosa) is a dicot weed in the Asteraceae family.  In Mexico this weed first evolved resistance to Group 9 (Legacy G) herbicides in 2014 and infests Lime, and sour.   Group 9 (Legacy G) herbicides are known as Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (Inhibition of EPSP synthase).  Research has shown that these particular biotypes are resistant to glyphosate and they may be cross-resistant to other Group 9 (Legacy G) 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 Oct 15, 2014 )

Common NameHairy Beggarticks
SpeciesBidens pilosa
GroupInhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
LocationMexico, Gulf of Mexico
Situation(s)Lime, and sour
Contributors - (Alphabetically)Hugo Cruz-Hipólito, Rafael De Prado, and Ja Dominguez Valenzuela 
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Confirmation Tests

Greenhouse trials comparing a known susceptible Hairy Beggarticks biotype with this Hairy Beggarticks 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 HRAC Group 9 resistant Hairy Beggarticks 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 9 (Legacy G) resistant Hairy Beggarticks from Mexico please update the database.
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Research Asociate
Universidad De Córdoba
Química Agrícola Y Edafología
Campus Universitario De Rabanales Edif. C-3 3ª Planta
Córdoba, 14002
Email Hugo Cruz-Hipólito
Research Asociate
Universidad De Cordoba
Qvimica Agricola Y Edafologa
E T S Ingenieros Agronomos
PO Box 119
Cordoba, E-14080, Andalusia
Email Rafael De Prado
Universidad Autónoma Chapingo
Parasitología Agrícola
Area De Malezas Departamento De Parasitología Agricola
Texcoco, 56230, Andalusia
Email Ja Dominguez Valenzuela


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Mexico have been instrumental in providing you this information. Particular thanks is given to Hugo Cruz-Hipólito, Rafael De Prado, and Ja Dominguez Valenzuela for providing detailed information.
Herbicide Resistant Hairy Beggarticks Globally
(Bidens pilosa)
Herbicide Resistant Hairy Beggarticks Globally
(Bidens pilosa)
Drag a column header and drop it here to group by that column
Herbicide Resistant Hairy Beggarticks Globally
(Bidens pilosa)
#CountryFirstYearSituationActive IngredientsSite of Action
1 BrazilBrazil 1993 Soybean chlorimuron-ethyl, imazaquin, imazethapyr, nicosulfuron, and pyrithiobac-sodium 5 Inhibition of Acetolactate Synthase (B/2)
32Bidens pilosaHairy Beggarticks42
2 BrazilBrazil 2016 Corn (maize), and Soybean atrazine, and imazethapyr 5 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
PSII inhibitors - Serine 264 Binders (C1 C2/5)
32Bidens pilosaHairy Beggarticks14053
3 KenyaKenya 1991 Coffee paraquat 26 PS I Electron Diversion (D/22)
32Bidens pilosaHairy Beggarticks381
4 MexicoMexico 2014 Lime, and sour glyphosate 29 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
32Bidens pilosaHairy Beggarticks9923
Literature about Similar Cases

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