(Papaver rhoeas)

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

Greece, Boeotia
Corn Poppy (Papaver rhoeas) is a dicot weed in the Papaveraceae family.  In Greece this weed first evolved multiple resistance (to 2 herbicide sites of action) in 2002 and infests 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, iodosulfuron-methyl-sodium, and mesosulfuron-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 Oct 03, 2019 )

Common NameCorn Poppy
SpeciesPapaver rhoeas
GroupALS inhibitors (B/2)
Auxin Mimics (O/4)
Herbicides2,4-D, iodosulfuron-methyl-sodium, and mesosulfuron-methyl
LocationGreece, Boeotia
Contributors - (Alphabetically)Christophe Délye, Vaya Kati, and Laura Scarabel 
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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

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

Studies on the mechanism of resistance of multiple resistant Corn Poppy from Greece 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 multiple resistant Corn Poppy from Greece please update the database.
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Chargé de Recherches
17 rue de Sully
Dijon, F-21000, Burgundy
Email Christophe Délye
Web   : Web Site Link
Benaki Phytopathological Institute
Pesticides Control & Phytopharmacy
8 Stefanou Delta str.
Kifissia, 14561, Attiki
Email Vaya Kati
Web   : Web Site Link
Institute of Agroenvironmental and Forest Biology
National Research Council (CNR)
viale dell'Università 16
Legnaro (PD), 35020, Attiki
Email Laura Scarabel
Web   : Web Site Link


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Greece have been instrumental in providing you this information. Particular thanks is given to Christophe Délye, Vaya Kati, and Laura Scarabel 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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