International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
(Amaranthus blitum (ssp. oleraceus))

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

United States, New Jersey
Livid Amaranth (Amaranthus blitum (ssp. oleraceus)) is a dicot weed in the Amaranthaceae family.  In New Jersey this weed first evolved resistance to Group 2 (Legacy B) herbicides in 1993 and infests Cabbages, Lettuce, and Onions.   Group 2 (Legacy B) herbicides are known as Inhibition of Acetolactate Synthase (Inhibition of Acetolactate Synthase ).  Research has shown that these particular biotypes are resistant to imazethapyr and they may be cross-resistant to other Group 2 (Legacy B) herbicides.

The 'Group' letters/numbers that you see throughout this web site refer to the classification of herbicides by their site of action. To see a full list of herbicides and HRAC herbicide classifications click here.

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QUIK STATS (last updated Sep 15, 2000 )

Common NameLivid Amaranth
SpeciesAmaranthus blitum (ssp. oleraceus)
GroupInhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
LocationUnited States, New Jersey
Situation(s)Cabbages, Lettuce, and Onions
Contributors - (Alphabetically)Bradley Majek 
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Bradley Majek
Great Meadows, NJ

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Bradley Majek
Resistant to all tested ALS inibitors, including imidazonlinones and SU's. Resistance developed within 3 years of continuous and exclusive use of Pursuit for control.

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Confirmation Tests

Field, and Laboratory trials comparing a known susceptible Livid Amaranth biotype with this Livid Amaranth biotype have been used to confirm resistance. For further information on the tests conducted please contact the local weed scientists that provided this information.

Genetic studies on HRAC Group 2 resistant Livid Amaranth have not been reported to the site.  There may be a note below or an article discussing the genetics of this biotype in the Fact Sheets and Other Literature
Mechanism of Resistance

The mechanism of resistance for this biotype is either unknown or has not been entered in the database.  If you know anything about the mechanism of resistance for this biotype then please update the database.
Relative Fitness

There is no record of differences in fitness or competitiveness of these resistant biotypes when compared to that of normal susceptible biotypes.  If you have any information pertaining to the fitness of Group 2 (Legacy B) resistant Livid Amaranth from New Jersey please update the database.
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Extension Weed Specialist
Rutgers University
Department of Plant Biology and Pathology
121 Northville Rd.
Bridgeton, 08302, New Jersey
United States
Email Bradley Majek
Web   : Web Site Link


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in New Jersey have been instrumental in providing you this information. Particular thanks is given to Bradley Majek for providing detailed information.
Herbicide Resistant Livid Amaranth Globally
(Amaranthus blitum (ssp. oleraceus))
Herbicide Resistant Livid Amaranth Globally
(Amaranthus blitum (ssp. oleraceus))
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Herbicide Resistant Livid Amaranth Globally
(Amaranthus blitum (ssp. oleraceus))
#CountryFirstYearSituationActive IngredientsSite of Action
1 FranceFrance 1981 Corn (maize) atrazine 17 PSII inhibitors - Serine 264 Binders (C1 C2/5)
13Amaranthus blitum (ssp. oleraceus)Livid Amaranth454
2 MalaysiaMalaysia 1990 Vegetables paraquat 28 PS I Electron Diversion (D/22)
13Amaranthus blitum (ssp. oleraceus)Livid Amaranth137
3 SwitzerlandSwitzerland 1978 Grapes simazine 41 PSII inhibitors - Serine 264 Binders (C1 C2/5)
13Amaranthus blitum (ssp. oleraceus)Livid Amaranth196
4 United States (New Jersey) United StatesNew Jersey1993 Cabbages, Lettuce, and Onions imazethapyr 45 Inhibition of Acetolactate Synthase (B/2)
13Amaranthus blitum (ssp. oleraceus)Livid Amaranth1167
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