(Papaver rhoeas)

Multiple Resistance: 2 Sites of Action
ALS inhibitors (B/2)
Auxin Mimics (O/4)

Corn Poppy (Papaver rhoeas) is a dicot weed in the Papaveraceae family.  In Spain this weed first evolved multiple resistance (to 2 herbicide sites of action) in 1993 and infests Cereals, and Wheat.  Multiple resistance has evolved to herbicides in the Groups B/2, and O/4.  These particular biotypes are known to have resistance to 2,4-D, and tribenuron-methyl and they may be cross-resistant to other herbicides in the Groups B/2, and O/4.

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 Jan 10, 2003 )

Common NameCorn Poppy
SpeciesPapaver rhoeas
GroupALS inhibitors (B/2)
Auxin Mimics (O/4)
Herbicides2,4-D, and tribenuron-methyl
Situation(s)Cereals, and Wheat
Contributors - (Alphabetically)Alicia Cirujeda, and Andreu Taberner 
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Alicia Cirujeda
Alguaire (Lleida) (Northeastern Spain). Northeastern (Catalonia) and North (Castilla Leon and Navarra) of Spain.

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Alicia Cirujeda
Herbicide control of resistant Papaver rhoeas L. to tribemiron and 2,4-D.

Alicia Cirujeda, Ramon Tarrago,  Jordi Recasens, Andreu Tabener

During the cropping season 1998/99, four field experiments were conducted in winter cereal fields with a high infestation of resistant Papaver rhoeas in Catalonia (North-eastern Spain). Two fields had resistant poppies to both herbicides and two had poppies resistant to tribenuron but susceptible to 2,4-D. Seventeen combinations of pre- and early and late post-emergence herbicides were tested. The experiments were designed in three blocks containing the randomly distributed 10 m2 pots. Application was done with an AZO sprayer. Evaluations were done counting living plants in a square meter three times in each plot every fortnight after treatment, and Abbot efficacy of each evaluation was calculated. The pre-emergence herbicides tested had high efficacy in all the tested fields where they were applied: pendimethalin (1.65 L a.i. ha-1, trifluralin + linuron (0.72 L a.i. ha-1 + 0.36La.i. ha-1) and trifluralin + chlortoluron (0.72 L a.i. ha-1.+-l.25 L a.i. ha-1)... No phytotoxicity on the cereals was detected in any case. In early post-emergence, the most effective group was the HBNs. The mixtures containing bromoxynil gave a high control in all fields, followed by the mixtures containing ioxinil. Diflufenican in mixture with MCPA (0.0375 + 0.375 L a.i. ha-1) gave good results in three locations. Isoproturon + diflufenican (1.35 + 0.126 L a.i. ha-1) controlled P. rhoeas at two locations only. Good control was achieved with tribenuron + metribuzin (0.015 + 0.07 g a.i. ha-1) and with triclopyr + chlortoluron (0.48 + 1.25 L a.i. ha-1) at also two locations. Terbutryn + triasulfuron (0.297 + 0.03 L a.i. ha-1) had high efficacy in only one location. In late post-emergence, 2,4-D (0.6 L a.i. ha-1) gave good control only at the two susceptible fields to this herbicide. The mixture 2,4-D with florasulam (0.3 + 0.00625 L a.i. ha-1) was effective at the same two sites only. Dicamba at 0.192 L a.i. ha-1 gave high control at two locations only. A short-term control of the herbicide resistance of P. rhoeas to tribenuron and to 2,4-D seems possible with chemical methods, especially by using HBN's or pre-emergence herbicides.

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Andreu Taberner
These 2,4-D resistant corn poppy populations are found in the Northeastern (Catalonia) and North (Castilla Leon and Navarra) of Spain. Fortunately they remain susceptible to ioxinil and bromoxynil.

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Vaya Kati

KATI V, SCARABEL L, THIERY-LANFRANCHI D, KIOLEOGLOU V, LIBEROPOULOU S, & DELYE C (2019). Multiple resistance ofPapaver rhoeas L. to 2,4-D and acetolactate synthase inhibitors in four European countries. Weed Research 59, 367–376.


The issue of cross- or multiple resistance to acetolactate synthase (ALS) inhibitors and the auxinic herbicide 2,4-D was investigated in Papaver rhoeas L., a common and troublesome weed in winter cereals, in a broad-scale study across four European countries. A combination of herbicide sensitivity bioassays and molecular assays targeting mutations involved in resistance was conducted on 27 populations of P. rhoeas originating from Greece (9), Italy (5), France (10) and Spain (3). Plants resistant to the field rate of 2,4-D were observed in 25 of the 27 populations assayed, in frequencies ranging from 5% to 85%. Plants resistant to ALS-inhibiting herbicides (sulfonylureas) were present in 24 of the 27 populations, in frequencies ranging from 4% to 100%. Plants resistant to 2,4-D co-occurred with plants resistant to sulfonylureas in 23 populations. In four of these, the probability of presence of plants with cross- or multiple resistance to 2,4D and sulfonylureas was higher than 0.5. ALS genotyping of plants from the field populations or of their progenies, identified ALS alleles carrying a mutation at codon Pro197 or Trp574 in 2,4-D-sensitive and in 2,4-D-resistant plants. The latter case confirmed multiple resistance to 2,4-D and ALS inhibitors at the level of individual plants in all four countries investigated. This study is the first to identify individual plants with multiple resistance in P. rhoeas, an attribute rarely assessed in other weed species, but one with significant implications in designing chemical control strategies.

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Confirmation Tests

Field, Greenhouse, and Laboratory trials comparing a known susceptible Corn Poppy biotype with this Corn Poppy 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 B, O/2, 4 resistant Corn Poppy 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 multiple resistant Corn Poppy from Spain please update the database.
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Unidad de Sanidad Vegetal, Centro de Investigación y Tecnología
Agroalimentaria de Aragón (CITA)
Avda. Montañana 930
Zaragoza, 50059 , Aragon
Email Alicia Cirujeda
University of Lleida
Secció De Malherbologia
Servicio Proteccisn Vegetales
PO Box 619
Lleida, 25198, Aragon
Email Andreu Taberner


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Spain have been instrumental in providing you this information. Particular thanks is given to Alicia Cirujeda, and Andreu Taberner for providing detailed information.
Herbicide Resistant Corn Poppy Globally
(Papaver rhoeas)
Herbicide Resistant Corn Poppy Globally
(Papaver rhoeas)
Drag a column header and drop it here to group by that column
Herbicide Resistant Corn Poppy Globally
(Papaver rhoeas)
#CountryFirstYearSituationActive IngredientsSite of Action
1 BelgiumBelgium 2014 Wheat florasulam, and metsulfuron-methyl 3 ALS inhibitors (B/2)
123Papaver rhoeasCorn Poppy10960
2 DenmarkDenmark 2003 Wheat florasulam, iodosulfuron-methyl-sodium, and tribenuron-methyl 13 ALS inhibitors (B/2)
123Papaver rhoeasCorn Poppy5346
3 FranceFrance 2007 Wheat iodosulfuron-methyl-sodium, mesosulfuron-methyl, and metsulfuron-methyl 17 ALS inhibitors (B/2)
123Papaver rhoeasCorn Poppy5517
4 FranceFrance 2015 Wheat 2,4-D 17 Auxin Mimics (O/4)
123Papaver rhoeasCorn Poppy18176
5 FranceFrance 2016 Cereals 2,4-D, iodosulfuron-methyl-sodium, MCPA, mesosulfuron-methyl, and metsulfuron-methyl 17 Multiple Resistance: 2 Sites of Action
ALS inhibitors (B/2)
Auxin Mimics (O/4)
123Papaver rhoeasCorn Poppy15054
6 GermanyGermany 2012 Cereals, and Rapeseed florasulam, and imazamox 18 ALS inhibitors (B/2)
123Papaver rhoeasCorn Poppy6743
7 GreeceGreece 1998 Winter wheat chlorsulfuron, florasulam, imazamox, pyrithiobac-sodium, thifensulfuron-methyl, triasulfuron, and tribenuron-methyl 19 ALS inhibitors (B/2)
123Papaver rhoeasCorn Poppy1142
8 GreeceGreece 2002 Wheat 2,4-D, iodosulfuron-methyl-sodium, and mesosulfuron-methyl 19 Multiple Resistance: 2 Sites of Action
ALS inhibitors (B/2)
Auxin Mimics (O/4)
123Papaver rhoeasCorn Poppy18174
9 ItalyItaly 1998 Durum wheat florasulam, iodosulfuron-methyl-sodium, and tribenuron-methyl 24 ALS inhibitors (B/2)
123Papaver rhoeasCorn Poppy1140
10 ItalyItaly 1998 Wheat 2,4-D, iodosulfuron-methyl-sodium, and tribenuron-methyl 24 Multiple Resistance: 2 Sites of Action
ALS inhibitors (B/2)
Auxin Mimics (O/4)
123Papaver rhoeasCorn Poppy5679
11 ItalyItaly 1998 Wheat 2,4-D 24 Auxin Mimics (O/4)
123Papaver rhoeasCorn Poppy5680
12 PolandPoland 2014 Winter wheat tribenuron-methyl 33 ALS inhibitors (B/2)
123Papaver rhoeasCorn Poppy10983
13 SpainSpain 1993 Cereals, and Wheat 2,4-D, and tribenuron-methyl 38 Multiple Resistance: 2 Sites of Action
ALS inhibitors (B/2)
Auxin Mimics (O/4)
123Papaver rhoeasCorn Poppy185
14 SwedenSweden 2011 Winter wheat amidosulfuron, iodosulfuron-methyl-sodium, and propoxycarbazone-sodium 40 ALS inhibitors (B/2)
123Papaver rhoeasCorn Poppy8913
15 United KingdomUnited Kingdom 2001 Cereals metsulfuron-methyl 44 ALS inhibitors (B/2)
123Papaver rhoeasCorn Poppy5169
Literature about Similar Cases

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PERMISSION MUST BE OBTAINED FIRST if you intend to base a significant portion of a scientific paper on data derived from this site. Citation:
Heap, I.  The International Herbicide-Resistant Weed Database.  Online.  Saturday, April 17, 2021 .  Available Copyright © 1993- 2021 All rights reserved. Fair use of this material is encouraged. Proper citation is requested.