International Survey of Herbicide-Resistant Weeds

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(Sorghum halepense)

ALS inhibitors (B/2)

Johnsongrass (Sorghum halepense) is a monocot weed in the Poaceae family.  In Hungary this weed first evolved resistance to Group B/2 herbicides in 2015 and infests Corn (maize), and Fallow.   Group B/2 herbicides are known as ALS inhibitors (Inhibition of Acetolactate Synthase ).  Research has shown that these particular biotypes are resistant to foramsulfuron, and nicosulfuron and they may be cross-resistant to other Group B/2 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 24, 2019 )

Common NameJohnsongrass
SpeciesSorghum halepense
GroupALS inhibitors (B/2)
Herbicidesforamsulfuron, and nicosulfuron
Situation(s)Corn (maize), and Fallow
Contributors - (Alphabetically)Gábor Kukorelli, and Gábor Markó 
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Gábor Markó

English Translation of Hungarian Abstract.


1Department of Plant Pathology, Szent István University, Ménesi út 44, H-1118 Budapest, Hungary; *marko.gabor3@ 2Behavioral Ecology Group, Department of Systematic Zoology and Ecology, Eötvös Loránd University, Pázmány Péter sétány 1/C, H-1117 Budapest, Hungary

The nicosulfuron resistance is anincreasingly important problem afflicting the modern agricultural fields due to the massive application of the sulphonylureas.  The present immoderate use of such herbicides would radically transform the traditional approach of the chemical weed control, especially in the dominant crops.  According to the recent field observations, independent nicosulfuron resistant Johnsongrass (Sorghum halepense) populations have been developed in Fejér County Hungary.  In the present Johnsongrass study, our aims were twofold: first, serving evidence for the prescence of nicosulfuron resistance; second, testing the relative effectivity of the nicosulfuron based herbicides in resistant and susceptible poplulations.  We selected three similar, independent agricultural fields in terms of ecology and production technology.  We treated the Johnsongrass populations by different nicosulfuron products (alone and combining with other herbicide agents) along with concentration gradient and we estimated the change in the weed cover after the treatments. We found that a population among the three observed fields contained Johnsongrass individuals which are resistant against the nicosulfuron.  We found also that officially permitted herbicide dose was not always sufficient to control the resistant population.  We predicted a radical change in the chemical weed control due to the increasing spread of the herbicide resistant weed biotypes as a new risk factor.  In the future, the local pest control should also contain frequency dependent (non-chemical) solutions against the resistant biotypes.

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Confirmation Tests

Field trials comparing a known susceptible Johnsongrass biotype with this Johnsongrass 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 Group B/2 resistant Johnsongrass 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 B/2 resistant Johnsongrass from Hungary please update the database.
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Faculty of Agricultural and Food Sciences
Vár Tér 2.
Mosonmagyaróvár, H-9200, Győr-Moson-Sopron
Email Gábor Kukorelli
associate professor
Szent István University
Plant Pathology
44 Ménesi út
Budapest, 1156, Budapest
Email Gábor Markó


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Hungary have been instrumental in providing you this information. Particular thanks is given to Gábor Kukorelli, and Gábor Markó for providing detailed information.
Herbicide Resistant Johnsongrass Globally
(Sorghum halepense)
Herbicide Resistant Johnsongrass Globally
(Sorghum halepense)
Drag a column header and drop it here to group by that column
Herbicide Resistant Johnsongrass Globally
(Sorghum halepense)
#CountryFirstYearSituationActive IngredientsSite of Action
1 ArgentinaArgentina 2005 Soybean glyphosate 48 EPSP synthase inhibitors (G/9)
166Sorghum halepenseJohnsongrass5271
2 ArgentinaArgentina 2015 Soybean haloxyfop-methyl 48 ACCase inhibitors (A/1)
166Sorghum halepenseJohnsongrass10979
3 ArgentinaArgentina 2015 Soybean glyphosate, and haloxyfop-methyl 48 Multiple Resistance: 2 Sites of Action
ACCase inhibitors (A/1)
EPSP synthase inhibitors (G/9)
166Sorghum halepenseJohnsongrass10991
4 Australia (Queensland) AustraliaQueensland2019 Fallow glyphosate 1 EPSP synthase inhibitors (G/9)
166Sorghum halepenseJohnsongrass18193
5 ChileChile 2009 Corn (maize) nicosulfuron 8 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass5693
6 GreeceGreece 2005 Cotton propaquizafop, and quizalofop-ethyl 19 ACCase inhibitors (A/1)
166Sorghum halepenseJohnsongrass5393
7 HungaryHungary 2015 Corn (maize), and Fallow foramsulfuron, and nicosulfuron 20 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass17119
8 IsraelIsrael 2006 Carrots, Cotton, Onions, and Peanut (groundnut) clethodim, fluazifop-P-butyl, and haloxyfop-methyl 23 ACCase inhibitors (A/1)
166Sorghum halepenseJohnsongrass5301
9 IsraelIsrael 2017 Cotton, and Watermelon rimsulfuron 23 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass18159
10 ItalyItaly 2005 Soybean, and Tomatoes fluazifop-P-butyl, haloxyfop-methyl, propaquizafop, and quizalofop-ethyl 24 ACCase inhibitors (A/1)
166Sorghum halepenseJohnsongrass5354
11 ItalyItaly 2007 Corn (maize) nicosulfuron 24 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass8905
12 MexicoMexico 2009 Corn (maize) foramsulfuron, nicosulfuron, primisulfuron-methyl, and rimsulfuron 29 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass5475
13 SerbiaSerbia 2014 Corn (maize) imazamox, nicosulfuron, propoxycarbazone-sodium, pyroxsulam, and rimsulfuron 245 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass15065
14 SerbiaSerbia 2017 Soybean fenoxaprop-P-ethyl, fluazifop-P-butyl, haloxyfop-methyl, propaquizafop, and quizalofop-ethyl 245 ACCase inhibitors (A/1)
166Sorghum halepenseJohnsongrass17146
15 SpainSpain 2015 Corn (maize) nicosulfuron 38 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass11000
16 United States (Mississippi) United StatesMississippi1991 Cotton, and Cropland fenoxaprop-P-ethyl, fluazifop-P-butyl, and quizalofop-ethyl 45 ACCase inhibitors (A/1)
166Sorghum halepenseJohnsongrass250
17 United States (Kentucky) United StatesKentucky1991 Soybean fluazifop-P-butyl 45 ACCase inhibitors (A/1)
166Sorghum halepenseJohnsongrass488
18 United States (Mississippi) United StatesMississippi1992 Cotton pendimethalin 45 Microtubule Assembly inhibitors (K1/3)
166Sorghum halepenseJohnsongrass328
19 United States (Tennessee) United StatesTennessee1995 Cotton, and Soybean fluazifop-P-butyl, and quizalofop-ethyl 45 ACCase inhibitors (A/1)
166Sorghum halepenseJohnsongrass1106
20 United States (Virginia) United StatesVirginia1995 Soybean sethoxydim 45 ACCase inhibitors (A/1)
166Sorghum halepenseJohnsongrass1108
21 United States (Louisiana) United StatesLouisiana1997 Cotton clethodim, and fluazifop-P-butyl 45 ACCase inhibitors (A/1)
166Sorghum halepenseJohnsongrass1044
22 United States (Texas) United StatesTexas2000 Corn (maize) imazethapyr, and nicosulfuron 45 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass5091
23 United States (West Virginia) United StatesWest Virginia2004 Corn (maize) nicosulfuron 45 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass7775
24 United States (Indiana) United StatesIndiana2005 Corn (maize), and Soybean nicosulfuron 45 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass5282
25 United States (Kentucky) United StatesKentucky2006 Corn (maize) foramsulfuron, nicosulfuron, and primisulfuron-methyl 45 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass7880
26 United States (Arkansas) United StatesArkansas2007 Soybean glyphosate 45 EPSP synthase inhibitors (G/9)
166Sorghum halepenseJohnsongrass5344
27 United States (Mississippi) United StatesMississippi2008 Soybean glyphosate 45 EPSP synthase inhibitors (G/9)
166Sorghum halepenseJohnsongrass5558
28 United States (Louisiana) United StatesLouisiana2010 Soybean glyphosate 45 EPSP synthase inhibitors (G/9)
166Sorghum halepenseJohnsongrass5522
29 VenezuelaVenezuela 2010 Corn (maize) foramsulfuron, iodosulfuron-methyl-sodium, and nicosulfuron 80 ALS inhibitors (B/2)
166Sorghum halepenseJohnsongrass5553
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