INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE
Most Recent Cases of Herbicide Resistant Weeds Entered into the Database
(click on a column header to sort or click on a country for details)
#Date Last UpdatedSpeciesCountryFirst YearSite of Action
1 August 30, 2021Amaranthus retroflexusUkraineUkraine 2020230 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		16Redroot Pigweed20231
2 August 30, 2021Polygonum pensylvanicumUnited States (Arkansas) United StatesArkansas202045 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		135Pennsylvania Smartweed20230
3 August 30, 2021Amaranthus palmeriUnited States (Arkansas) United StatesArkansas202045 Inhibition of Glutamine Synthetase HRAC Group 10 (Legacy H)
 		14Palmer Amaranth20229
4 August 16, 2021Digitaria insularisParaguayParaguay 202046 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		239Sourgrass20223
5 August 11, 2021Alopecurus myosuroidesSwitzerlandSwitzerland 201941 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		6Blackgrass20228
6 August 11, 2021Lolium perenne ssp. multiflorumSwitzerlandSwitzerland 201841 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		110Italian Ryegrass20226
7 August 11, 2021Lolium perenne ssp. multiflorumSwitzerlandSwitzerland 201841 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
 		110Italian Ryegrass20227
8 August 11, 2021Sorghum halepenseSerbiaSerbia 2018245 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		166Johnsongrass20225
9 August 11, 2021Ambrosia artemisiifoliaSerbiaSerbia 2019245 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		18Common Ragweed20224
10 May 5, 2021Chloris radiataColombiaColombia 201910 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		340Radiate Fingergrass19224
11 April 29, 2021Amaranthus tuberculatus (=A. rudis)United States (North Carolina) United StatesNorth Carolina202045 Multiple Resistance: 5 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
Inhibition of Hydroxyphenyl Pyruvate Dioxygenase HRAC Group 27 (Legacy F2)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		219Tall Waterhemp19222
12 March 13, 2021Amaranthus palmeriUnited States (Tennessee) United StatesTennessee202045 Multiple Resistance: 2 Sites of Action
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
Auxin Mimics HRAC Group 4 (Legacy O)
 		14Palmer Amaranth19221
13 March 11, 2021Raphanus raphanistrumAustralia (Western Australia) AustraliaWestern Australia20201 Multiple Resistance: 4 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Inhibition of Hydroxyphenyl Pyruvate Dioxygenase HRAC Group 27 (Legacy F2)
Very Long-Chain Fatty Acid Synthesis inhibitorsHRAC Group 15 (Legacy K3 N)
Auxin Mimics HRAC Group 4 (Legacy O)
 		141Wild Radish19219
14 March 10, 2021Salsola tragusArgentinaArgentina 201948 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		147Russian-thistle19218
15 March 9, 2021Oryza sativa var. sylvaticaTurkeyTurkey 202071 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		242Red Rice19217
16 February 26, 2021Arctotheca calendulaAustralia (Western Australia) AustraliaWestern Australia20201 Multiple Resistance: 3 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Phytoene Desaturase inhibitorsHRAC Group 12 (Legacy F1)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		21Capeweed19216
17 February 23, 2021Rapistrum rugosumAustralia (New South Wales ) AustraliaNew South Wales 20211 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		142Turnipweed19215
18 February 23, 2021Echinochloa crus-galli var. crus-galliAustralia (New South Wales ) AustraliaNew South Wales 20211 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
 		79Barnyardgrass19214
19 February 4, 2021Euphorbia heterophyllaBrazilBrazil 20195 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		87Wild Poinsettia19213
20 February 4, 2021Digitaria insularisBrazilBrazil 20205 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		239Sourgrass19212
21 February 1, 2021Echinochloa crus-galli var. crus-galliBrazilBrazil 20205 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		79Barnyardgrass19211
22 December 16, 2020Bromus rubensSpainSpain 201838 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		324Red Brome18210
23 November 26, 2020Bromus madritensisSpainSpain 201838 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		352Compact Brome18209
24 November 13, 2020Eleusine indicaItalyItaly 201924 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		81Goosegrass18208
25 October 20, 2020Amaranthus tuberculatus (=A. rudis)IsraelIsrael 201923 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		219Tall Waterhemp18207
26 October 7, 2020Amaranthus palmeriUnited States (Connecticut) United StatesConnecticut201945 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		14Palmer Amaranth18206
27 October 1, 2020Apera spica-ventiBelgiumBelgium 20193 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		20Silky Windgrass18199
28 September 21, 2020Poa annuaNew ZealandNew Zealand 202030 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
 		130Annual Bluegrass18203
29 September 10, 2020Avena fatuaIrelandIreland 201981 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
 		28Wild Oat18200
30 July 3, 2020Conyza canadensisFranceFrance 201917 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		61Horseweed18198
31 June 22, 2020Chloris barbata = (C. inflate)MexicoMexico 201829 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		53Swollen Fingergrass18197
32 June 22, 2020Sorghum halepenseAustralia (Queensland) AustraliaQueensland20191 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		166Johnsongrass18193
33 June 22, 2020Hordeum murinum ssp. leporinumSpainSpain 201838 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		98Hare Barley18192
34 May 20, 2020Eleusine indicaUnited States (Alabama) United StatesAlabama201945 PS I Electron Diversion HRAC Group 22 (Legacy D)
 		81Goosegrass18191
35 January 22, 2020Avena fatuaAustralia (Queensland) AustraliaQueensland20181 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		28Wild Oat18187
36 November 28, 2019Amaranthus hybridus (syn: quitensis)BrazilBrazil 20185 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		12Smooth Pigweed18184
37 November 28, 2019Secale cerealeUnited States (Colorado) United StatesColorado201845 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		351Feral Rye18182
38 November 28, 2019Echinochloa crus-galli var. crus-galliArgentinaArgentina 201948 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		79Barnyardgrass18183
39 November 22, 2019Avena sterilis ssp. ludovicianaAustralia (New South Wales ) AustraliaNew South Wales 20181 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		30Sterile oat18186
40 October 24, 2019Capsella bursa-pastorisNorwayNorway 201931 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		41Shepherd's-purse18169
41 October 1, 2019Carduus acanthoidesArgentinaArgentina 201948 Multiple Resistance: 2 Sites of Action
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
Auxin Mimics HRAC Group 4 (Legacy O)
 		348Plumeless Thistle18173
42 September 24, 2019Oryza sativa var. sylvaticaColombiaColombia 201810 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		242Red Rice18170
43 September 2, 2019Rapistrum rugosumSpainSpain 201838 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		142Turnipweed18171
44 August 19, 2019Conyza sumatrensisTurkeyTurkey 201971 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		65Sumatran Fleabane18164
45 August 5, 2019Lithospermum arvenseChinaChina 20199 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		341Corn Gromwell18168
46 July 31, 2019Chloris radiataColombiaColombia 201910 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		340Radiate Fingergrass18165
47 May 13, 2019Galinsoga parvifloraFranceFrance 201817 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		339Gallant Soldier18162
48 May 13, 2019Conyza sumatrensisAustralia (Queensland) AustraliaQueensland20181 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		65Sumatran Fleabane18161
49 January 9, 2019Amaranthus palmeriUnited States (Kansas) United StatesKansas201845 Auxin Mimics HRAC Group 4 (Legacy O)
 		14Palmer Amaranth18151
50 December 15, 2018Lolium perenne ssp. multiflorumUnited States (Washington) United StatesWashington201845 Very Long-Chain Fatty Acid Synthesis inhibitorsHRAC Group 15 (Legacy K3 N)
 		110Italian Ryegrass17154
51 December 15, 2018Lolium perenne ssp. multiflorumUnited KingdomUnited Kingdom 201844 Very Long-Chain Fatty Acid Synthesis inhibitorsHRAC Group 15 (Legacy K3 N)
 		110Italian Ryegrass17153
52 December 15, 2018Lolium perenne ssp. multiflorumFranceFrance 201817 Very Long-Chain Fatty Acid Synthesis inhibitorsHRAC Group 15 (Legacy K3 N)
 		110Italian Ryegrass17152
53 December 15, 2018Lolium perenne ssp. multiflorumUnited States (Oregon) United StatesOregon201845 Very Long-Chain Fatty Acid Synthesis inhibitorsHRAC Group 15 (Legacy K3 N)
 		110Italian Ryegrass17151
54 November 9, 2018Bidens subalternansParaguayParaguay 201846 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
 		194Greater Beggarticks17150
55 October 10, 2018Conyza canadensisUnited States (Oklahoma) United StatesOklahoma201845 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		61Horseweed17149
56 October 2, 2018Conyza sumatrensisAustralia (Queensland) AustraliaQueensland20181 PS I Electron Diversion HRAC Group 22 (Legacy D)
 		65Sumatran Fleabane17148
57 July 16, 2018Oryza sativa var. sylvaticaMalaysiaMalaysia 201828 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
 		242Red Rice17145
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