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 November 24, 2025Poa annuaUnited States (Oregon) United StatesOregon202545 Inhibition of Microtubule AssemblyHRAC Group 3 (Legacy K1)
130Annual Bluegrass33279
2 November 24, 2025Poa annuaUnited States (Oregon) United StatesOregon202545 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
130Annual Bluegrass33281
3 November 24, 2025Poa annuaUnited States (Oregon) United StatesOregon202545 PS I Electron Diversion HRAC Group 22 (Legacy D)
130Annual Bluegrass33280
4 November 24, 2025Poa annuaUnited States (Oregon) United StatesOregon202545 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
130Annual Bluegrass33278
5 November 24, 2025Poa annuaUnited States (Oregon) United StatesOregon202545 Inhibition of Cellulose Synthesis HRAC Group 29 (Legacy L)
130Annual Bluegrass33277
6 November 8, 2025Ischaemum rugosumBrazilBrazil 20245 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
99Saramollagrass33276
7 November 8, 2025Amaranthus palmeriUnited States (North Carolina) United StatesNorth Carolina202545 Multiple Resistance: 5 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
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)
Auxin Mimics HRAC Group 4 (Legacy O)
14Palmer Amaranth33275
8 October 9, 2025Helianthus annuusMexicoMexico 202329 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
95Common Sunflower32283
9 October 9, 2025Digitaria sanguinalisFranceFrance 202317 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Inhibition of Hydroxyphenyl Pyruvate Dioxygenase HRAC Group 27 (Legacy F2)
77Large Crabgrass32286
10 October 9, 2025Echinochloa crus-galli var. crus-galliFranceFrance 201717 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Inhibition of Hydroxyphenyl Pyruvate Dioxygenase HRAC Group 27 (Legacy F2)
79Barnyardgrass32285
11 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
12 August 28, 2025Amaranthus hybridus (syn: quitensis)BoliviaBolivia 20154 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
12Smooth Pigweed32281
13 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
14 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
15 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
16 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
17 August 19, 2025Lolium rigidumMoroccoMorocco 2023166 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
112Rigid Ryegrass29272
18 August 19, 2025Lolium rigidumMoroccoMorocco 2023166 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
112Rigid Ryegrass29271
19 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
20 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
21 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
22 August 18, 2025Arctotheca calendulaAustralia (Western Australia) AustraliaWestern Australia20211 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
21Capeweed32276
23 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
24 July 30, 2025Conyza sumatrensisArgentinaArgentina 201448 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
65Sumatran Fleabane32270
25 July 30, 2025Amaranthus palmeriUnited States (Arkansas) United StatesArkansas202345 Auxin Mimics HRAC Group 4 (Legacy O)
14Palmer Amaranth32271
26 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
27 July 24, 2025Kochia scopariaArgentinaArgentina 202348 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
101Kochia31277
28 July 24, 2025Daucus carotaNew ZealandNew Zealand 202530 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
76Wild Carrot32274
29 July 24, 2025Stellaria mediaEstoniaEstonia 202199 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
168Common Chickweed30270
30 July 24, 2025Amaranthus palmeriUnited States (North Carolina) United StatesNorth Carolina202545 Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
14Palmer Amaranth32272
31 July 23, 2025Amaranthus tuberculatus (=A. rudis)ItalyItaly 201024 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
219Tall Waterhemp32269
32 July 23, 2025Amaranthus palmeriItalyItaly 201824 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
14Palmer Amaranth32268
33 June 5, 2025Poa trivialisIrelandIreland 202381 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
350Roughstalk Bluegrass31279
34 May 30, 2025Eleusine indicaArgentinaArgentina 201448 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
81Goosegrass31278
35 May 30, 2025Panicum dichotomiflorumSpainSpain 202238 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
122Fall Panicum31276
36 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
37 May 30, 2025Conyza sumatrensisBoliviaBolivia 20244 PS I Electron Diversion HRAC Group 22 (Legacy D)
65Sumatran Fleabane31271
38 May 30, 2025Rapistrum rugosumArgentinaArgentina 201848 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
142Turnipweed31273
39 May 22, 2025Amaranthus palmeriArgentinaArgentina 202548 Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
14Palmer Amaranth31274
40 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
41 April 24, 2025Conyza canadensisMexicoMexico 201829 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
61Horseweed31270
42 March 3, 2025Polygonum convolvulus (=Fallopia convolvulus)United States (Kansas) United StatesKansas202045 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
88Wild Buckwheat31269
43 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
44 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
45 January 27, 2025Conyza canadensisUnited States (New York) United StatesNew York202445 PS I Electron Diversion HRAC Group 22 (Legacy D)
61Horseweed30268
46 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
47 December 5, 2024Steinchisma laxumColombiaColombia 202310 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
1358Lax Panicgrass27271
48 December 2, 2024Setaria viridisUkraineUkraine 2024230 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
153Green Foxtail29269
49 November 27, 2024Alopecurus myosuroidesFranceFrance 202217 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
6Blackgrass29265
50 November 6, 2024Lolium rigidumTunisiaTunisia 202378 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
112Rigid Ryegrass29275
51 October 24, 2024Atriplex patulaFranceFrance 201917 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
26Halberdleaf Orach29266
52 October 10, 2024Lolium rigidumAlgeriaAlgeria 2023115 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
112Rigid Ryegrass29274
53 October 10, 2024Lolium rigidumAlgeriaAlgeria 2023115 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
112Rigid Ryegrass29273
54 October 9, 2024Galium spuriumAustriaAustria 20242 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
93False Cleavers29264
55 September 23, 2024Echinochloa colonaPakistanPakistan 202486 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
78Junglerice29279
56 September 17, 2024Amaranthus albusIsraelIsrael 202323 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
7Tumble Pigweed29280
57 September 5, 2024Avena fatuaPakistanPakistan 202486 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
28Wild Oat29281
58 August 24, 2024Alopecurus myosuroidesFranceFrance 202017 Very Long-Chain Fatty Acid Synthesis inhibitorsHRAC Group 15 (Legacy K3 N)
6Blackgrass29267
59 August 11, 2024Schoenoplectus juncoidesChinaChina 20249 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
196Rock Bulrush29282
60 August 6, 2024Echinochloa crus-pavonisChinaChina 20249 Auxin Mimics HRAC Group 4 (Legacy O)
193Gulf Cockspur29283
61 August 3, 2024Amaranthus palmeriUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
14Palmer Amaranth29270
62 July 21, 2024Chenopodium albumCanada (New Brunswick) CanadaNew Brunswick20187 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
47Common Lambsquarters28276
63 July 14, 2024Ambrosia artemisiifoliaCanada (Prince Edward Island) CanadaPrince Edward Island20237 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
18Common Ragweed28275
64 July 12, 2024Amaranthus retroflexusCanada (Prince Edward Island) CanadaPrince Edward Island20237 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
16Redroot Pigweed28274
65 July 8, 2024Chenopodium albumCanada (Prince Edward Island) CanadaPrince Edward Island20187 PSII inhibitors - Serine 264 Binders HRAC Group 5 (Legacy C1 C2)
47Common Lambsquarters28273
66 June 15, 2024Oryza sativa var. sylvaticaArgentinaArgentina 201848 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
242Red Rice27289
67 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
68 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
69 May 24, 2024Bidens pilosaBrazilBrazil 20225 Inhibition of Protoporphyrinogen Oxidase HRAC Group 14 (Legacy E)
32Hairy Beggarticks27288
70 May 24, 2024Digitaria sanguinalisSwitzerlandSwitzerland 202141 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
77Large Crabgrass27290
71 May 24, 2024Amaranthus hybridus (syn: quitensis)South AfricaSouth Africa 202437 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
12Smooth Pigweed27287
72 May 19, 2024Glebionis segetumGreeceGreece 202119 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
2358Corn Marigold28272
73 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
74 April 20, 2024Echinochloa phyllopogon (=E. oryzicola)PortugalPortugal 202034 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
178Late Watergrass28268
75 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
76 March 25, 2024Chloris truncataSpainSpain 202338 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
262Windmill Grass27293
77 March 18, 2024Conyza canadensisUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
61Horseweed27286
78 March 18, 2024Conyza bonariensisUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
60Hairy Fleabane27285
79 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
80 March 5, 2024Papaver rhoeasPortugalPortugal 201834 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
123Corn Poppy28271
81 March 3, 2024Lolium perenne ssp. multiflorumPortugalPortugal 201934 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
110Italian Ryegrass28266
82 February 24, 2024Echinochloa crus-galli var. crus-galliPortugalPortugal 201834 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
79Barnyardgrass28265
83 February 20, 2024Echinochloa crus-galli var. crus-galliPortugalPortugal 201534 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
79Barnyardgrass28264
84 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
85 February 18, 2024Echinochloa phyllopogon (=E. oryzicola)PortugalPortugal 201534 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
178Late Watergrass27294
86 January 21, 2024Bromus diandrusNew ZealandNew Zealand 202430 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
197Ripgut Brome27283
87 November 19, 2023Avena sterilisSpainSpain 202338 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
29Sterile Oat27282
88 November 3, 2023Amaranthus hybridus (syn: quitensis)ItalyItaly 201824 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
12Smooth Pigweed27281
89 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
90 October 25, 2023Echinochloa crus-galli var. crus-galliThailandThailand 202147 Inhibition of Cellulose Synthesis HRAC Group 29 (Legacy L)
79Barnyardgrass27275
91 September 26, 2023Monochoria vaginalisIndonesiaIndonesia 202222 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
202Arrowleafed Monochoria27274
92 August 5, 2023Panicum miliaceum var. ruderale Kitag.ChinaChina 20239 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
1359Wild Panicgrass27273
93 June 23, 2023Ammannia multifloraChinaChina 20229 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
1360Many Flowered Ammannia27279
94 June 8, 2023Galium spuriumGreeceGreece 202219 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
93False Cleavers27278
95 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
96 June 3, 2023Ambrosia artemisiifoliaUnited States (Michigan) United StatesMichigan202245 Auxin Mimics HRAC Group 4 (Legacy O)
18Common Ragweed27277
97 March 30, 2023Digitaria ciliarisChinaChina 20219 Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
225Southern Crabgrass27272
98 March 12, 2023Echinochloa phyllopogon (=E. oryzicola)ChinaChina 20239 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
178Late Watergrass27267
99 March 11, 2023Ammannia auriculataChinaChina 20239 Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
183Eared Redstem27280
100 February 2, 2023Leptochloa chinensisChinaChina 20239 Inhibition of Hydroxyphenyl Pyruvate Dioxygenase HRAC Group 27 (Legacy F2)
223Chinese Sprangletop27268
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