International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
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 19, 2025Lolium rigidumAlgeriaAlgeria 2023115 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)
112Rigid Ryegrass29277
2 August 19, 2025Lolium rigidumTunisiaTunisia 202378 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)
112Rigid Ryegrass29276
3 August 19, 2025Lolium rigidumMoroccoMorocco 2023166 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
112Rigid Ryegrass29272
4 August 19, 2025Lolium rigidumMoroccoMorocco 2023166 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
112Rigid Ryegrass29271
5 August 19, 2025Lolium rigidumMoroccoMorocco 2023166 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)
112Rigid Ryegrass29278
6 August 19, 2025Papaver rhoeasTunisiaTunisia 202578 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Auxin Mimics HRAC Group 4 (Legacy O)
123Corn Poppy32278
7 August 19, 2025Papaver rhoeasMoroccoMorocco 2025166 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Auxin Mimics HRAC Group 4 (Legacy O)
123Corn Poppy32277
8 August 18, 2025Arctotheca calendulaAustralia (Western Australia) AustraliaWestern Australia20211 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
21Capeweed32276
9 August 18, 2025Kochia scopariaUnited States (South Dakota) United StatesSouth Dakota202345 Multiple Resistance: 3 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
101Kochia32275
10 July 30, 2025Conyza sumatrensisArgentinaArgentina 201448 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
65Sumatran Fleabane32270
11 July 30, 2025Amaranthus palmeriUnited States (Arkansas) United StatesArkansas202345 Auxin Mimics HRAC Group 4 (Legacy O)
14Palmer Amaranth32271
12 July 25, 2025Lolium perenne ssp. multiflorumUnited States (New York) United StatesNew York202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
110Italian Ryegrass32273
13 July 24, 2025Kochia scopariaArgentinaArgentina 202348 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
101Kochia31277
14 July 24, 2025Daucus carotaNew ZealandNew Zealand 202530 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
76Wild Carrot32274
15 July 24, 2025Stellaria mediaEstoniaEstonia 202199 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
168Common Chickweed30270
16 July 24, 2025Amaranthus palmeriUnited States (North Carolina) United StatesNorth Carolina202545 Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
14Palmer Amaranth32272
17 July 23, 2025Amaranthus tuberculatus (=A. rudis)ItalyItaly 201024 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
219Tall Waterhemp32269
18 July 23, 2025Amaranthus palmeriItalyItaly 201824 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
14Palmer Amaranth32268
19 June 5, 2025Poa trivialisIrelandIreland 202381 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
350Roughstalk Bluegrass31279
20 May 30, 2025Eleusine indicaArgentinaArgentina 201448 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
81Goosegrass31278
21 May 30, 2025Panicum dichotomiflorumSpainSpain 202238 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
122Fall Panicum31276
22 May 30, 2025Kochia scopariaSpainSpain 202238 Multiple Resistance: 3 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
Auxin Mimics HRAC Group 4 (Legacy O)
101Kochia31275
23 May 30, 2025Conyza sumatrensisBoliviaBolivia 20244 PS I Electron Diversion HRAC Group 22 (Legacy D)
65Sumatran Fleabane31271
24 May 30, 2025Rapistrum rugosumArgentinaArgentina 201848 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
142Turnipweed31273
25 May 22, 2025Amaranthus palmeriArgentinaArgentina 202548 Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
14Palmer Amaranth31274
26 May 12, 2025Lolium rigidumSpainSpain 201538 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)
112Rigid Ryegrass31272
27 April 24, 2025Conyza canadensisMexicoMexico 201829 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
61Horseweed31270
28 March 3, 2025Polygonum convolvulus (=Fallopia convolvulus)United States (Kansas) United StatesKansas202045 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
88Wild Buckwheat31269
29 February 24, 2025Brassica rapa (=B. campestris)MexicoMexico 202129 Multiple Resistance: 3 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
Auxin Mimics HRAC Group 4 (Legacy O)
36Birdsrape Mustard31268
30 January 27, 2025Amaranthus palmeriUnited States (New York) United StatesNew York202445 Multiple Resistance: 2 Sites of Action
PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
14Palmer Amaranth30269
31 January 27, 2025Conyza canadensisUnited States (New York) United StatesNew York202445 PS I Electron Diversion HRAC Group 22 (Legacy D)
61Horseweed30268
32 December 7, 2024Amaranthus palmeriTurkeyTurkey 202371 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 Amaranth29268
33 December 5, 2024Steinchisma laxumColombiaColombia 202310 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
1358Lax Panicgrass27271
34 December 2, 2024Setaria viridisUkraineUkraine 2024230 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
153Green Foxtail29269
35 November 27, 2024Alopecurus myosuroidesFranceFrance 202217 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
6Blackgrass29265
36 November 6, 2024Lolium rigidumTunisiaTunisia 202378 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
112Rigid Ryegrass29275
37 October 24, 2024Atriplex patulaFranceFrance 201917 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
26Halberdleaf Orach29266
38 October 10, 2024Lolium rigidumAlgeriaAlgeria 2023115 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
112Rigid Ryegrass29274
39 October 10, 2024Lolium rigidumAlgeriaAlgeria 2023115 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
112Rigid Ryegrass29273
40 October 9, 2024Galium spuriumAustriaAustria 20242 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
93False Cleavers29264
41 September 23, 2024Echinochloa colonaPakistanPakistan 202486 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
78Junglerice29279
42 September 17, 2024Amaranthus albusIsraelIsrael 202323 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
7Tumble Pigweed29280
43 September 5, 2024Avena fatuaPakistanPakistan 202486 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
28Wild Oat29281
44 August 24, 2024Alopecurus myosuroidesFranceFrance 202017 Very Long-Chain Fatty Acid Synthesis inhibitorsHRAC Group 15 (Legacy K3 N)
6Blackgrass29267
45 August 11, 2024Schoenoplectus juncoidesChinaChina 20249 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
196Rock Bulrush29282
46 August 6, 2024Echinochloa crus-pavonisChinaChina 20249 Auxin Mimics HRAC Group 4 (Legacy O)
193Gulf Cockspur29283
47 August 3, 2024Amaranthus palmeriUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
14Palmer Amaranth29270
48 July 21, 2024Chenopodium albumCanada (New Brunswick) CanadaNew Brunswick20187 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
47Common Lambsquarters28276
49 July 14, 2024Ambrosia artemisiifoliaCanada (Prince Edward Island) CanadaPrince Edward Island20237 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
18Common Ragweed28275
50 July 12, 2024Amaranthus retroflexusCanada (Prince Edward Island) CanadaPrince Edward Island20237 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
16Redroot Pigweed28274
51 July 8, 2024Chenopodium albumCanada (Prince Edward Island) CanadaPrince Edward Island20187 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
47Common Lambsquarters28273
52 June 15, 2024Oryza sativa var. sylvaticaArgentinaArgentina 201848 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
242Red Rice27289
53 June 8, 2024Conyza bonariensisUruguayUruguay 202273 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)
60Hairy Fleabane27291
54 June 6, 2024Cyperus difformisPortugalPortugal 202334 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
PSII inhibitors - Histidine 215 Binders HRAC Group 6 (Legacy C3)
71Smallflower Umbrella Sedge28270
55 May 24, 2024Bidens pilosaBrazilBrazil 20225 Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
32Hairy Beggarticks27288
56 May 24, 2024Digitaria sanguinalisSwitzerlandSwitzerland 202141 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
77Large Crabgrass27290
57 May 24, 2024Amaranthus hybridus (syn: quitensis)South AfricaSouth Africa 202437 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
12Smooth Pigweed27287
58 May 19, 2024Glebionis segetumGreeceGreece 202119 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
2358Corn Marigold28272
59 May 4, 2024Echinochloa phyllopogon (=E. oryzicola)PortugalPortugal 202034 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)
178Late Watergrass28269
60 April 20, 2024Echinochloa phyllopogon (=E. oryzicola)PortugalPortugal 202034 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
178Late Watergrass28268
61 April 9, 2024Papaver rhoeasPortugalPortugal 201834 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Auxin Mimics HRAC Group 4 (Legacy O)
123Corn Poppy28267
62 March 25, 2024Chloris truncataSpainSpain 202338 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
262Windmill Grass27293
63 March 18, 2024Conyza canadensisUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
61Horseweed27286
64 March 18, 2024Conyza bonariensisUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
60Hairy Fleabane27285
65 March 18, 2024Amaranthus palmeriUnited States (Iowa) United StatesIowa202245 Multiple Resistance: 4 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 Hydroxyphenyl Pyruvate Dioxygenase HRAC Group 27 (Legacy F2)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
14Palmer Amaranth27284
66 March 5, 2024Papaver rhoeasPortugalPortugal 201834 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
123Corn Poppy28271
67 March 3, 2024Lolium perenne ssp. multiflorumPortugalPortugal 201934 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
110Italian Ryegrass28266
68 February 24, 2024Echinochloa crus-galli var. crus-galliPortugalPortugal 201834 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
79Barnyardgrass28265
69 February 20, 2024Echinochloa crus-galli var. crus-galliPortugalPortugal 201534 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
79Barnyardgrass28264
70 February 20, 2024Amaranthus palmeriSpainSpain 202338 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 Amaranth27292
71 February 18, 2024Echinochloa phyllopogon (=E. oryzicola)PortugalPortugal 201534 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
178Late Watergrass27294
72 January 21, 2024Bromus diandrusNew ZealandNew Zealand 202430 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
197Ripgut Brome27283
73 November 19, 2023Avena sterilisSpainSpain 202338 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
29Sterile Oat27282
74 November 9, 2023Amaranthus tuberculatus (=A. rudis)United States (Idaho) United StatesIdaho202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
219Tall Waterhemp27264
75 November 3, 2023Amaranthus hybridus (syn: quitensis)ItalyItaly 201824 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
12Smooth Pigweed27281
76 October 30, 2023Amaranthus tuberculatus (=A. rudis)United States (Iowa) United StatesIowa202145 Auxin Mimics HRAC Group 4 (Legacy O)
219Tall Waterhemp27263
77 October 26, 2023Conyza bonariensisJordanJordan 202255 Multiple Resistance: 2 Sites of Action
PS I Electron Diversion HRAC Group 22 (Legacy D)
Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
60Hairy Fleabane27269
78 October 25, 2023Echinochloa crus-galli var. crus-galliThailandThailand 202147 Inhibition of Cellulose Synthesis HRAC Group 29 (Legacy L)
79Barnyardgrass27275
79 October 18, 2023Poa annuaIrelandIreland 202181 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)
130Annual Bluegrass27262
80 September 26, 2023Monochoria vaginalisIndonesiaIndonesia 202222 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
202Arrowleafed Monochoria27274
81 September 14, 2023Ambrosia artemisiifoliaUkraineUkraine 2023230 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
18Common Ragweed26266
82 September 5, 2023Echinochloa crus-galli var. crus-galliBrazilBrazil 20185 Multiple Resistance: 3 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Inhibition of Cellulose Synthesis HRAC Group 29 (Legacy L)
Auxin Mimics HRAC Group 4 (Legacy O)
79Barnyardgrass26265
83 September 5, 2023Bidens subalternansBrazilBrazil 20235 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
194Greater Beggarticks26263
84 September 5, 2023Sagittaria montevidensisBrazilBrazil 20235 Auxin Mimics HRAC Group 4 (Legacy O)
146California Arrowhead26264
85 August 28, 2023Bromus diandrusAustralia (Western Australia) AustraliaWestern Australia20201 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
197Ripgut Brome26262
86 August 5, 2023Panicum miliaceum var. ruderale Kitag.ChinaChina 20239 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
1359Wild Panicgrass27273
87 July 13, 2023Echinochloa crus-galli var. crus-galliIndiaIndia 201721 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
79Barnyardgrass25264
88 July 11, 2023Amaranthus palmeriUnited States (Colorado) United StatesColorado202145 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
14Palmer Amaranth25265
89 July 6, 2023Digitaria sanguinalisNew ZealandNew Zealand 202230 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
77Large Crabgrass25262
90 June 29, 2023Hordeum jubatumCanada (Alberta) CanadaAlberta20227 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
358Foxtail Barley25263
91 June 23, 2023Ammannia multifloraChinaChina 20229 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
1360Many Flowered Ammannia27279
92 June 8, 2023Galium spuriumGreeceGreece 202219 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
93False Cleavers27278
93 June 5, 2023Plantago lanceolataSouth AfricaSouth Africa 202237 Multiple Resistance: 2 Sites of Action
PS I Electron Diversion HRAC Group 22 (Legacy D)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
220Buckhorn Plantain27276
94 June 3, 2023Ambrosia artemisiifoliaUnited States (Michigan) United StatesMichigan202245 Auxin Mimics HRAC Group 4 (Legacy O)
18Common Ragweed27277
95 April 4, 2023Lolium perenne ssp. multiflorumChinaChina 20229 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 Ryegrass27266
96 March 30, 2023Digitaria ciliarisChinaChina 20219 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
225Southern Crabgrass27272
97 March 12, 2023Echinochloa phyllopogon (=E. oryzicola)ChinaChina 20239 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
178Late Watergrass27267
98 March 11, 2023Ammannia auriculataChinaChina 20239 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
183Eared Redstem27280
99 February 2, 2023Leptochloa chinensisChinaChina 20239 Inhibition of Hydroxyphenyl Pyruvate Dioxygenase HRAC Group 27 (Legacy F2)
223Chinese Sprangletop27268
100 April 9, 2022Amaranthus palmeriUnited States (Idaho) United StatesIdaho202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
14Palmer Amaranth27265
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