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 July 30, 2025Amaranthus palmeriUnited States (Arkansas) United StatesArkansas202345 Auxin Mimics (O/4)
 		14Palmer Amaranth32271
2 July 25, 2025Lolium perenne ssp. multiflorumUnited States (New York) United StatesNew York202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		110Italian Ryegrass32273
3 July 24, 2025Kochia scopariaArgentinaArgentina 202348 Inhibition of Acetolactate Synthase (B/2)
 		101Kochia31277
4 July 24, 2025Daucus carotaNew ZealandNew Zealand 202530 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		76Wild Carrot32274
5 July 24, 2025Stellaria mediaEstoniaEstonia 202199 Inhibition of Acetolactate Synthase (B/2)
 		168Common Chickweed30270
6 July 24, 2025Amaranthus palmeriUnited States (North Carolina) United StatesNorth Carolina202545 Inhibition of Protoporphyrinogen Oxidase (E/14)
 		14Palmer Amaranth32272
7 July 23, 2025Amaranthus palmeriItalyItaly 201824 Inhibition of Acetolactate Synthase (B/2)
 		14Palmer Amaranth32268
8 June 5, 2025Poa trivialisIrelandIreland 202381 Inhibition of Acetolactate Synthase (B/2)
 		350Roughstalk Bluegrass31279
9 May 30, 2025Panicum dichotomiflorumSpainSpain 202238 Inhibition of Acetolactate Synthase (B/2)
 		122Fall Panicum31276
10 May 30, 2025Kochia scopariaSpainSpain 202238 Multiple Resistance: 3 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
Auxin Mimics (O/4)
 		101Kochia31275
11 May 30, 2025Conyza sumatrensisBoliviaBolivia 20244 PS I Electron Diversion (D/22)
 		65Sumatran Fleabane31271
12 May 30, 2025Rapistrum rugosumArgentinaArgentina 201848 Inhibition of Acetolactate Synthase (B/2)
 		142Turnipweed31273
13 May 22, 2025Amaranthus palmeriArgentinaArgentina 202548 Inhibition of Protoporphyrinogen Oxidase (E/14)
 		14Palmer Amaranth31274
14 April 24, 2025Conyza canadensisMexicoMexico 201829 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		61Horseweed31270
15 March 3, 2025Polygonum convolvulus (=Fallopia convolvulus)United States (Kansas) United StatesKansas202045 Inhibition of Acetolactate Synthase (B/2)
 		88Wild Buckwheat31269
16 February 24, 2025Brassica rapa (=B. campestris)MexicoMexico 202129 Multiple Resistance: 3 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
Auxin Mimics (O/4)
 		36Birdsrape Mustard31268
17 January 27, 2025Amaranthus palmeriUnited States (New York) United StatesNew York202445 Multiple Resistance: 2 Sites of Action
PSII inhibitors - Serine 264 Binders (C1 C2/5)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		14Palmer Amaranth30269
18 January 27, 2025Conyza canadensisUnited States (New York) United StatesNew York202445 PS I Electron Diversion (D/22)
 		61Horseweed30268
19 December 7, 2024Amaranthus palmeriTurkeyTurkey 202371 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		14Palmer Amaranth29268
20 December 5, 2024Steinchisma laxumColombiaColombia 202310 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		1358Lax Panicgrass27271
21 December 2, 2024Setaria viridisUkraineUkraine 2024230 Inhibition of Acetolactate Synthase (B/2)
 		153Green Foxtail29269
22 November 27, 2024Alopecurus myosuroidesFranceFrance 202217 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		6Blackgrass29265
23 November 6, 2024Lolium rigidumTunisiaTunisia 202378 Inhibition of Acetolactate Synthase (B/2)
 		112Rigid Ryegrass29275
24 November 6, 2024Lolium rigidumAlgeriaAlgeria 2023115 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase (A/1)
Inhibition of Acetolactate Synthase (B/2)
 		112Rigid Ryegrass29277
25 November 6, 2024Lolium rigidumTunisiaTunisia 202378 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase (A/1)
Inhibition of Acetolactate Synthase (B/2)
 		112Rigid Ryegrass29276
26 October 24, 2024Atriplex patulaFranceFrance 201917 PSII inhibitors - Serine 264 Binders (C1 C2/5)
 		26Halberdleaf Orach29266
27 October 10, 2024Lolium rigidumAlgeriaAlgeria 2023115 Inhibition of Acetolactate Synthase (B/2)
 		112Rigid Ryegrass29274
28 October 10, 2024Lolium rigidumAlgeriaAlgeria 2023115 Inhibition of Acetyl CoA Carboxylase (A/1)
 		112Rigid Ryegrass29273
29 October 9, 2024Galium spuriumAustriaAustria 20242 Inhibition of Acetolactate Synthase (B/2)
 		93False Cleavers29264
30 September 28, 2024Lolium rigidumMoroccoMorocco 2023166 Inhibition of Acetolactate Synthase (B/2)
 		112Rigid Ryegrass29272
31 September 28, 2024Lolium rigidumMoroccoMorocco 2023166 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase (A/1)
Inhibition of Acetolactate Synthase (B/2)
 		112Rigid Ryegrass29278
32 September 28, 2024Lolium rigidumMoroccoMorocco 2023166 Inhibition of Acetyl CoA Carboxylase (A/1)
 		112Rigid Ryegrass29271
33 September 23, 2024Echinochloa colonaPakistanPakistan 202486 Inhibition of Acetolactate Synthase (B/2)
 		78Junglerice29279
34 September 17, 2024Amaranthus albusIsraelIsrael 202323 Inhibition of Acetolactate Synthase (B/2)
 		7Tumble Pigweed29280
35 September 5, 2024Avena fatuaPakistanPakistan 202486 Inhibition of Acetyl CoA Carboxylase (A/1)
 		28Wild Oat29281
36 August 29, 2024Amaranthus palmeriUnited States (Kansas) United StatesKansas202145 Multiple Resistance: 6 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
PSII inhibitors - Serine 264 Binders (C1 C2/5)
Inhibition of Protoporphyrinogen Oxidase (E/14)
Inhibition of Hydroxyphenyl Pyruvate Dioxygenase (F2/27)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
Auxin Mimics (O/4)
 		14Palmer Amaranth24257
37 August 24, 2024Alopecurus myosuroidesFranceFrance 202017 Very Long-Chain Fatty Acid Synthesis inhibitors (K3 N/15)
 		6Blackgrass29267
38 August 11, 2024Schoenoplectus juncoidesChinaChina 20249 Inhibition of Acetolactate Synthase (B/2)
 		196Rock Bulrush29282
39 August 6, 2024Echinochloa crus-pavonisChinaChina 20249 Auxin Mimics (O/4)
 		193Gulf Cockspur29283
40 August 3, 2024Amaranthus palmeriUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		14Palmer Amaranth29270
41 July 21, 2024Chenopodium albumCanada (New Brunswick) CanadaNew Brunswick20187 PSII inhibitors - Serine 264 Binders (C1 C2/5)
 		47Common Lambsquarters28276
42 July 14, 2024Ambrosia artemisiifoliaCanada (Prince Edward Island) CanadaPrince Edward Island20237 PSII inhibitors - Serine 264 Binders (C1 C2/5)
 		18Common Ragweed28275
43 July 12, 2024Amaranthus retroflexusCanada (Prince Edward Island) CanadaPrince Edward Island20237 PSII inhibitors - Serine 264 Binders (C1 C2/5)
 		16Redroot Pigweed28274
44 July 8, 2024Chenopodium albumCanada (Prince Edward Island) CanadaPrince Edward Island20187 PSII inhibitors - Serine 264 Binders (C1 C2/5)
 		47Common Lambsquarters28273
45 June 15, 2024Oryza sativa var. sylvaticaArgentinaArgentina 201848 Inhibition of Acetolactate Synthase (B/2)
 		242Red Rice27289
46 June 8, 2024Conyza bonariensisUruguayUruguay 202273 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		60Hairy Fleabane27291
47 June 6, 2024Cyperus difformisPortugalPortugal 202334 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
PSII inhibitors - Histidine 215 Binders (C3/6)
 		71Smallflower Umbrella Sedge28270
48 May 24, 2024Bidens pilosaBrazilBrazil 20225 Inhibition of Protoporphyrinogen Oxidase (E/14)
 		32Hairy Beggarticks27288
49 May 24, 2024Digitaria sanguinalisSwitzerlandSwitzerland 202141 Inhibition of Acetolactate Synthase (B/2)
 		77Large Crabgrass27290
50 May 24, 2024Amaranthus hybridus (syn: quitensis)South AfricaSouth Africa 202437 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		12Smooth Pigweed27287
51 May 19, 2024Glebionis segetumGreeceGreece 202119 Inhibition of Acetolactate Synthase (B/2)
 		2358Corn Marigold28272
52 May 4, 2024Echinochloa phyllopogon (=E. oryzicola)PortugalPortugal 202034 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase (A/1)
Inhibition of Acetolactate Synthase (B/2)
 		178Late Watergrass28269
53 April 20, 2024Echinochloa phyllopogon (=E. oryzicola)PortugalPortugal 202034 Inhibition of Acetyl CoA Carboxylase (A/1)
 		178Late Watergrass28268
54 April 9, 2024Papaver rhoeasPortugalPortugal 201834 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Auxin Mimics (O/4)
 		123Corn Poppy28267
55 March 25, 2024Chloris truncataSpainSpain 202338 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		262Windmill Grass27293
56 March 18, 2024Conyza canadensisUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		61Horseweed27286
57 March 18, 2024Conyza bonariensisUnited States (Oregon) United StatesOregon202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		60Hairy Fleabane27285
58 March 18, 2024Amaranthus palmeriUnited States (Iowa) United StatesIowa202245 Multiple Resistance: 4 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
PSII inhibitors - Serine 264 Binders (C1 C2/5)
Inhibition of Hydroxyphenyl Pyruvate Dioxygenase (F2/27)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		14Palmer Amaranth27284
59 March 5, 2024Papaver rhoeasPortugalPortugal 201834 Inhibition of Acetolactate Synthase (B/2)
 		123Corn Poppy28271
60 March 3, 2024Lolium perenne ssp. multiflorumPortugalPortugal 201934 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		110Italian Ryegrass28266
61 February 24, 2024Echinochloa crus-galli var. crus-galliPortugalPortugal 201834 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		79Barnyardgrass28265
62 February 20, 2024Amaranthus palmeriSpainSpain 202338 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		14Palmer Amaranth27292
63 January 21, 2024Bromus diandrusNew ZealandNew Zealand 202430 Inhibition of Acetolactate Synthase (B/2)
 		197Ripgut Brome27283
64 November 19, 2023Avena sterilisSpainSpain 202338 Inhibition of Acetyl CoA Carboxylase (A/1)
 		29Sterile Oat27282
65 November 9, 2023Amaranthus tuberculatus (=A. rudis)United States (Idaho) United StatesIdaho202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		219Tall Waterhemp27264
66 November 3, 2023Amaranthus hybridus (syn: quitensis)ItalyItaly 201824 Inhibition of Acetolactate Synthase (B/2)
 		12Smooth Pigweed27281
67 October 30, 2023Amaranthus tuberculatus (=A. rudis)United States (Iowa) United StatesIowa202145 Auxin Mimics (O/4)
 		219Tall Waterhemp27263
68 October 26, 2023Conyza bonariensisJordanJordan 202255 Multiple Resistance: 2 Sites of Action
PS I Electron Diversion (D/22)
Inhibition of Protoporphyrinogen Oxidase (E/14)
 		60Hairy Fleabane27269
69 October 25, 2023Echinochloa crus-galli var. crus-galliThailandThailand 202147 Inhibition of Cellulose Synthesis (L/26)
 		79Barnyardgrass27275
70 October 18, 2023Poa annuaIrelandIreland 202181 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase (A/1)
Inhibition of Acetolactate Synthase (B/2)
 		130Annual Bluegrass27262
71 September 26, 2023Monochoria vaginalisIndonesiaIndonesia 202222 Inhibition of Acetolactate Synthase (B/2)
 		202Arrowleafed Monochoria27274
72 September 14, 2023Ambrosia artemisiifoliaUkraineUkraine 2023230 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Protoporphyrinogen Oxidase (E/14)
 		18Common Ragweed26266
73 September 5, 2023Echinochloa crus-galli var. crus-galliBrazilBrazil 20185 Multiple Resistance: 3 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Cellulose Synthesis (L/26)
Auxin Mimics (O/4)
 		79Barnyardgrass26265
74 September 5, 2023Bidens subalternansBrazilBrazil 20235 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		194Greater Beggarticks26263
75 September 5, 2023Sagittaria montevidensisBrazilBrazil 20235 Auxin Mimics (O/4)
 		146California Arrowhead26264
76 August 28, 2023Bromus diandrusAustralia (Western Australia) AustraliaWestern Australia20201 Inhibition of Acetyl CoA Carboxylase (A/1)
 		197Ripgut Brome26262
77 August 5, 2023Panicum miliaceum var. ruderale Kitag.ChinaChina 20239 Inhibition of Acetolactate Synthase (B/2)
 		1359Wild Panicgrass27273
78 July 13, 2023Echinochloa crus-galli var. crus-galliIndiaIndia 201721 Inhibition of Acetolactate Synthase (B/2)
 		79Barnyardgrass25264
79 July 11, 2023Amaranthus palmeriUnited States (Colorado) United StatesColorado202145 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		14Palmer Amaranth25265
80 July 11, 2023Amaranthus powelliiCanada (Ontario) CanadaOntario20197 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Auxin Mimics (O/4)
 		15Powell Amaranth24243
81 July 6, 2023Digitaria sanguinalisNew ZealandNew Zealand 202230 Inhibition of Acetolactate Synthase (B/2)
 		77Large Crabgrass25262
82 June 29, 2023Hordeum jubatumCanada (Alberta) CanadaAlberta20227 Inhibition of Acetyl CoA Carboxylase (A/1)
 		358Foxtail Barley25263
83 June 23, 2023Ammannia multifloraChinaChina 20229 Inhibition of Acetolactate Synthase (B/2)
 		1360Many Flowered Ammannia27279
84 June 8, 2023Galium spuriumGreeceGreece 202219 Inhibition of Acetolactate Synthase (B/2)
 		93False Cleavers27278
85 June 5, 2023Plantago lanceolataSouth AfricaSouth Africa 202237 Multiple Resistance: 2 Sites of Action
PS I Electron Diversion (D/22)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		220Buckhorn Plantain27276
86 June 3, 2023Ambrosia artemisiifoliaUnited States (Michigan) United StatesMichigan202245 Auxin Mimics (O/4)
 		18Common Ragweed27277
87 May 9, 2023Echinochloa oryzoidesArgentinaArgentina 201648 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		261Early Watergrass25261
88 May 9, 2023Poa annuaUnited States (Georgia) United StatesGeorgia202245 Inhibition of Cellulose Synthesis (L/29)
 		130Annual Bluegrass25260
89 April 25, 2023Kochia scopariaCanada (Saskatchewan) CanadaSaskatchewan20217 Inhibition of Protoporphyrinogen Oxidase (E/14)
 		101Kochia25259
90 April 24, 2023Bromus commutatusUnited KingdomUnited Kingdom 202044 Inhibition of Acetolactate Synthase (B/2)
 		357Meadow Brome25258
91 April 23, 2023Bromus sterilisUnited KingdomUnited Kingdom 202044 Inhibition of Acetolactate Synthase (B/2)
 		289Poverty Brome25257
92 April 23, 2023Bromus diandrusUnited KingdomUnited Kingdom 202044 Inhibition of Acetolactate Synthase (B/2)
 		197Ripgut Brome25256
93 April 4, 2023Lolium perenne ssp. multiflorumChinaChina 20229 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase (A/1)
Inhibition of Acetolactate Synthase (B/2)
 		110Italian Ryegrass27266
94 March 30, 2023Digitaria ciliarisChinaChina 20219 Inhibition of Acetyl CoA Carboxylase (A/1)
 		225Southern Crabgrass27272
95 March 15, 2023Amaranthus retroflexusUnited States (North Carolina) United StatesNorth Carolina202245 Multiple Resistance: 3 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Protoporphyrinogen Oxidase (E/14)
Inhibition of Hydroxyphenyl Pyruvate Dioxygenase (F2/27)
 		16Redroot Pigweed24259
96 March 15, 2023Amaranthus retroflexusUnited States (North Carolina) United StatesNorth Carolina202245 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		16Redroot Pigweed24258
97 March 15, 2023Amaranthus retroflexusUnited States (North Carolina) United StatesNorth Carolina202045 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Protoporphyrinogen Oxidase (E/14)
 		16Redroot Pigweed22235
98 March 12, 2023Echinochloa phyllopogon (=E. oryzicola)ChinaChina 20239 Inhibition of Acetolactate Synthase (B/2)
 		178Late Watergrass27267
99 March 11, 2023Ammannia auriculataChinaChina 20239 Inhibition of Acetolactate Synthase (B/2)
 		183Eared Redstem27280
100 March 8, 2023Cyperus esculentusItalyItaly 201724 Inhibition of Acetolactate Synthase (B/2)
 		290Yellow Nutsedge24256
101 February 16, 2023Stellaria mediaUnited States (California) United StatesCalifornia202245 Inhibition of Acetolactate Synthase (B/2)
 		168Common Chickweed24253
102 February 2, 2023Leptochloa chinensisChinaChina 20239 Inhibition of Hydroxyphenyl Pyruvate Dioxygenase (F2/27)
 		223Chinese Sprangletop27268
103 January 31, 2023Amaranthus palmeriUruguayUruguay 202273 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		14Palmer Amaranth24254
104 January 31, 2023Amaranthus hybridus (syn: quitensis)UruguayUruguay 202273 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		12Smooth Pigweed24255
105 December 20, 2022Lolium perenne ssp. multiflorumUnited States (North Carolina) United StatesNorth Carolina202245 Multiple Resistance: 4 Sites of Action
Inhibition of Acetyl CoA Carboxylase (A/1)
Inhibition of Acetolactate Synthase (B/2)
PS I Electron Diversion (D/22)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		110Italian Ryegrass24251
106 December 4, 2022Amaranthus hybridus (syn: quitensis)ParaguayParaguay 202246 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		12Smooth Pigweed24252
107 November 22, 2022Chenopodium albumUkraineUkraine 2022230 Inhibition of Acetolactate Synthase (B/2)
 		47Common Lambsquarters24250
108 November 3, 2022Lolium perenne ssp. multiflorumSwitzerlandSwitzerland 202041 Multiple Resistance: 3 Sites of Action
Inhibition of Acetyl CoA Carboxylase (A/1)
Inhibition of Acetolactate Synthase (B/2)
PSII inhibitors - Serine 264 Binders (C1 C2/5)
 		110Italian Ryegrass24249
109 November 3, 2022Conyza canadensisSwitzerlandSwitzerland 202141 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		61Horseweed24248
110 November 3, 2022Conyza bonariensisSwitzerlandSwitzerland 202041 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		60Hairy Fleabane24247
111 October 24, 2022Panicum dichotomiflorumUnited States (Illinois) United StatesIllinois201945 Inhibition of Acetolactate Synthase (B/2)
 		122Fall Panicum24246
112 October 24, 2022Amaranthus tuberculatus (=A. rudis)UruguayUruguay 202273 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		219Tall Waterhemp24245
113 October 24, 2022Amaranthus palmeriUnited States (North Carolina) United StatesNorth Carolina202245 Inhibition of Glutamine Synthetase (H/10)
 		14Palmer Amaranth24244
114 October 6, 2022Amaranthus tuberculatus (=A. rudis)Canada (Ontario) CanadaOntario20217 Multiple Resistance: 5 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
PSII inhibitors - Serine 264 Binders (C1 C2/5)
Inhibition of Protoporphyrinogen Oxidase (E/14)
Inhibition of Hydroxyphenyl Pyruvate Dioxygenase (F2/27)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		219Tall Waterhemp24242
115 July 26, 2022Amaranthus palmeriSouth AfricaSouth Africa 201837 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		14Palmer Amaranth23244
116 July 11, 2022Amaranthus hybridus (syn: quitensis)ArgentinaArgentina 202148 Inhibition of Protoporphyrinogen Oxidase (E/14)
 		12Smooth Pigweed23243
117 July 6, 2022Echinochloa crus-galli var. crus-galliViet NamViet Nam 201774 Multiple Resistance: 2 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
Inhibition of Cellulose Synthesis (L/26)
 		79Barnyardgrass23242
118 June 13, 2022Amaranthus palmeriUnited States (North Carolina) United StatesNorth Carolina202245 PSII inhibitors - Serine 264 Binders (C1 C2/5)
 		14Palmer Amaranth23241
119 June 12, 2022Anthriscus caucalisGermanyGermany 201718 Inhibition of Acetolactate Synthase (B/2)
 		356Bur Chervil23240
120 April 27, 2022Digitaria sanguinalisArgentinaArgentina 201948 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		77Large Crabgrass23239
121 April 9, 2022Amaranthus palmeriUnited States (Idaho) United StatesIdaho202345 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		14Palmer Amaranth27265
122 March 18, 2022Sorghum halepenseUnited States (Missouri) United StatesMissouri201945 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		166Johnsongrass23238
123 March 14, 2022Cyperus difformisIndiaIndia 201721 Inhibition of Acetolactate Synthase (B/2)
 		71Smallflower Umbrella Sedge23236
124 March 11, 2022Poa annuaUnited States (Tennessee) United StatesTennessee201745 Multiple Resistance: 7 Sites of Action
Inhibition of Acetolactate Synthase (B/2)
PSII inhibitors - Serine 264 Binders (C1 C2/5)
Inhibition of Protoporphyrinogen Oxidase (E/14)
Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
Inhibition of Glutamine Synthetase (H/10)
Inhibition of Microtubule Assembly (K1/3)
Inhibition of Cellulose Synthesis (L/29)
 		130Annual Bluegrass23237
125 February 8, 2022Lolium perenne ssp. multiflorumCanada (Ontario) CanadaOntario20217 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (G/9)
 		110Italian Ryegrass22236
126 December 14, 2021Lolium perenne ssp. multiflorumIrelandIreland 202181 Multiple Resistance: 2 Sites of Action
Inhibition of Acetyl CoA Carboxylase (A/1)
Inhibition of Acetolactate Synthase (B/2)
 		110Italian Ryegrass21237
PERMISSION MUST BE OBTAINED FIRST if you intend to base a significant portion of a scientific paper on data derived from this site.
Cite this site as: Heap, I.  The International Survey of Herbicide Resistant Weeds.  Online.  Internet.  Sunday, August 10, 2025 .  Available  www.weedscience.org
Copyright � 1993- 2025 WeedScience.org All rights reserved. Fair use of this material is encouraged. Proper citation is requested.