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 28, 2025Sorghum bicolorBoliviaBolivia 20144 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)
165Shattercane32282
2 August 28, 2025Amaranthus hybridus (syn: quitensis)BoliviaBolivia 20154 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
12Smooth Pigweed32281
3 August 28, 2025Digitaria insularisBoliviaBolivia 20154 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)
239Sourgrass32280
4 August 28, 2025Eleusine indicaUnited States (North Carolina) United StatesNorth Carolina202245 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)
81Goosegrass32279
5 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
6 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
7 August 19, 2025Lolium rigidumMoroccoMorocco 2023166 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
112Rigid Ryegrass29272
8 August 19, 2025Lolium rigidumMoroccoMorocco 2023166 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
112Rigid Ryegrass29271
9 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
10 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
11 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
12 August 18, 2025Arctotheca calendulaAustralia (Western Australia) AustraliaWestern Australia20211 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
21Capeweed32276
13 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
14 July 30, 2025Conyza sumatrensisArgentinaArgentina 201448 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
65Sumatran Fleabane32270
15 July 30, 2025Amaranthus palmeriUnited States (Arkansas) United StatesArkansas202345 Auxin Mimics HRAC Group 4 (Legacy O)
14Palmer Amaranth32271
16 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
17 July 24, 2025Kochia scopariaArgentinaArgentina 202348 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
101Kochia31277
18 July 24, 2025Daucus carotaNew ZealandNew Zealand 202530 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
76Wild Carrot32274
19 July 24, 2025Stellaria mediaEstoniaEstonia 202199 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
168Common Chickweed30270
20 July 24, 2025Amaranthus palmeriUnited States (North Carolina) United StatesNorth Carolina202545 Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
14Palmer Amaranth32272
21 July 23, 2025Amaranthus tuberculatus (=A. rudis)ItalyItaly 201024 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
219Tall Waterhemp32269
22 July 23, 2025Amaranthus palmeriItalyItaly 201824 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
14Palmer Amaranth32268
23 June 5, 2025Poa trivialisIrelandIreland 202381 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
350Roughstalk Bluegrass31279
24 May 30, 2025Eleusine indicaArgentinaArgentina 201448 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
81Goosegrass31278
25 May 30, 2025Panicum dichotomiflorumSpainSpain 202238 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
122Fall Panicum31276
26 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
27 May 30, 2025Conyza sumatrensisBoliviaBolivia 20244 PS I Electron Diversion HRAC Group 22 (Legacy D)
65Sumatran Fleabane31271
28 May 30, 2025Rapistrum rugosumArgentinaArgentina 201848 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
142Turnipweed31273
29 May 22, 2025Amaranthus palmeriArgentinaArgentina 202548 Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
14Palmer Amaranth31274
30 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
31 April 24, 2025Conyza canadensisMexicoMexico 201829 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
61Horseweed31270
32 March 3, 2025Polygonum convolvulus (=Fallopia convolvulus)United States (Kansas) United StatesKansas202045 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
88Wild Buckwheat31269
33 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
34 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
35 January 27, 2025Conyza canadensisUnited States (New York) United StatesNew York202445 PS I Electron Diversion HRAC Group 22 (Legacy D)
61Horseweed30268
36 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
37 December 5, 2024Steinchisma laxumColombiaColombia 202310 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
1358Lax Panicgrass27271
38 December 2, 2024Setaria viridisUkraineUkraine 2024230 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
153Green Foxtail29269
39 November 27, 2024Alopecurus myosuroidesFranceFrance 202217 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
6Blackgrass29265
40 November 6, 2024Lolium rigidumTunisiaTunisia 202378 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
112Rigid Ryegrass29275
41 October 24, 2024Atriplex patulaFranceFrance 201917 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
26Halberdleaf Orach29266
42 October 10, 2024Lolium rigidumAlgeriaAlgeria 2023115 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
112Rigid Ryegrass29274
43 October 10, 2024Lolium rigidumAlgeriaAlgeria 2023115 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
112Rigid Ryegrass29273
44 October 9, 2024Galium spuriumAustriaAustria 20242 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
93False Cleavers29264
45 September 23, 2024Echinochloa colonaPakistanPakistan 202486 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
78Junglerice29279
46 September 17, 2024Amaranthus albusIsraelIsrael 202323 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
7Tumble Pigweed29280
47 September 5, 2024Avena fatuaPakistanPakistan 202486 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
28Wild Oat29281
48 August 24, 2024Alopecurus myosuroidesFranceFrance 202017 Very Long-Chain Fatty Acid Synthesis inhibitorsHRAC Group 15 (Legacy K3 N)
6Blackgrass29267
49 August 11, 2024Schoenoplectus juncoidesChinaChina 20249 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
196Rock Bulrush29282
50 August 6, 2024Echinochloa crus-pavonisChinaChina 20249 Auxin Mimics HRAC Group 4 (Legacy O)
193Gulf Cockspur29283
51 August 3, 2024Amaranthus palmeriUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
14Palmer Amaranth29270
52 July 21, 2024Chenopodium albumCanada (New Brunswick) CanadaNew Brunswick20187 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
47Common Lambsquarters28276
53 July 14, 2024Ambrosia artemisiifoliaCanada (Prince Edward Island) CanadaPrince Edward Island20237 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
18Common Ragweed28275
54 July 12, 2024Amaranthus retroflexusCanada (Prince Edward Island) CanadaPrince Edward Island20237 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
16Redroot Pigweed28274
55 July 8, 2024Chenopodium albumCanada (Prince Edward Island) CanadaPrince Edward Island20187 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
47Common Lambsquarters28273
56 June 15, 2024Oryza sativa var. sylvaticaArgentinaArgentina 201848 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
242Red Rice27289
57 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
58 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
59 May 24, 2024Bidens pilosaBrazilBrazil 20225 Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
32Hairy Beggarticks27288
60 May 24, 2024Digitaria sanguinalisSwitzerlandSwitzerland 202141 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
77Large Crabgrass27290
61 May 24, 2024Amaranthus hybridus (syn: quitensis)South AfricaSouth Africa 202437 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
12Smooth Pigweed27287
62 May 19, 2024Glebionis segetumGreeceGreece 202119 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
2358Corn Marigold28272
63 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
64 April 20, 2024Echinochloa phyllopogon (=E. oryzicola)PortugalPortugal 202034 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
178Late Watergrass28268
65 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
66 March 25, 2024Chloris truncataSpainSpain 202338 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
262Windmill Grass27293
67 March 18, 2024Conyza canadensisUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
61Horseweed27286
68 March 18, 2024Conyza bonariensisUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
60Hairy Fleabane27285
69 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
70 March 5, 2024Papaver rhoeasPortugalPortugal 201834 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
123Corn Poppy28271
71 March 3, 2024Lolium perenne ssp. multiflorumPortugalPortugal 201934 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
110Italian Ryegrass28266
72 February 24, 2024Echinochloa crus-galli var. crus-galliPortugalPortugal 201834 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
79Barnyardgrass28265
73 February 20, 2024Echinochloa crus-galli var. crus-galliPortugalPortugal 201534 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
79Barnyardgrass28264
74 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
75 February 18, 2024Echinochloa phyllopogon (=E. oryzicola)PortugalPortugal 201534 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
178Late Watergrass27294
76 January 21, 2024Bromus diandrusNew ZealandNew Zealand 202430 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
197Ripgut Brome27283
77 November 19, 2023Avena sterilisSpainSpain 202338 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
29Sterile Oat27282
78 November 9, 2023Amaranthus tuberculatus (=A. rudis)United States (Idaho) United StatesIdaho202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
219Tall Waterhemp27264
79 November 3, 2023Amaranthus hybridus (syn: quitensis)ItalyItaly 201824 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
12Smooth Pigweed27281
80 October 30, 2023Amaranthus tuberculatus (=A. rudis)United States (Iowa) United StatesIowa202145 Auxin Mimics HRAC Group 4 (Legacy O)
219Tall Waterhemp27263
81 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
82 October 25, 2023Echinochloa crus-galli var. crus-galliThailandThailand 202147 Inhibition of Cellulose Synthesis HRAC Group 29 (Legacy L)
79Barnyardgrass27275
83 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
84 September 26, 2023Monochoria vaginalisIndonesiaIndonesia 202222 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
202Arrowleafed Monochoria27274
85 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
86 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
87 September 5, 2023Bidens subalternansBrazilBrazil 20235 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
194Greater Beggarticks26263
88 September 5, 2023Sagittaria montevidensisBrazilBrazil 20235 Auxin Mimics HRAC Group 4 (Legacy O)
146California Arrowhead26264
89 August 28, 2023Bromus diandrusAustralia (Western Australia) AustraliaWestern Australia20201 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
197Ripgut Brome26262
90 August 5, 2023Panicum miliaceum var. ruderale Kitag.ChinaChina 20239 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
1359Wild Panicgrass27273
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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