(Alisma plantago-aquatica)

ALS inhibitors (B/2)

Common Waterplantain (Alisma plantago-aquatica) is a monocot weed in the Alismataceae family.  In Italy this weed first evolved resistance to Group B/2 herbicides in 1994 and infests Rice.   Group B/2 herbicides are known as ALS inhibitors (Inhibition of Acetolactate Synthase ).  Research has shown that these particular biotypes are resistant to bensulfuron-methyl, and cinosulfuron 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 15, 2000 )

Common NameCommon Waterplantain
SpeciesAlisma plantago-aquatica
GroupALS inhibitors (B/2)
Herbicidesbensulfuron-methyl, and cinosulfuron
Contributors - (Alphabetically)Maurizio Sattin 
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Maurizio Sattin
Pavaia, Vercelli, Milano, Biella. Piemonte, Lombardia

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Maurizio Sattin
There is a generalised cross resistance among the sulfonylureas (Azimsulfuron, Bensulfuron- methyl, Cinosulfuron, Ethoxysulfuron) as well as to the triazolopyrimidine (metosulam), but the level of resistance which appears to be very high for the sulfonylurea it is, in general, much lower for Metosulam. A few populations show very high level of resistance to both sulfonylureas and triazolopyrimidine. Although there is as yet no direct experimental proof, the available information suggests that the resistance mechanism could be a target-site. It is now estimated that between 10,000 and 15,000 ha are affected. Most resistant populations come from Novara Province and were selected by bensulfuron -methyl. The field histories suggest that resistance developed in a paddy rice monoculture system after at least three-four years using an ALS inhibitor alone for controlling these two species. Generally, resistance has not developed where the weed control strategy is devised in relation to the presence of red rice.

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Confirmation Tests

Field, and Greenhouse trials comparing a known susceptible Common Waterplantain biotype with this Common Waterplantain 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 Common Waterplantain 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 Common Waterplantain from Italy please update the database.
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Senior Weed Scientist
Italian National Research Council (cnr)
IBAF - Weed Science Unit
Viale dell'Università 16
Legnaro, 35020, Padova
Email Maurizio Sattin


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Italy have been instrumental in providing you this information. Particular thanks is given to Maurizio Sattin for providing detailed information.
Herbicide Resistant Common Waterplantain Globally
(Alisma plantago-aquatica)
Herbicide Resistant Common Waterplantain Globally
(Alisma plantago-aquatica)
Drag a column header and drop it here to group by that column
Herbicide Resistant Common Waterplantain Globally
(Alisma plantago-aquatica)
#CountryFirstYearSituationActive IngredientsSite of Action
1 ChileChile 2005 Rice bensulfuron-methyl 8 ALS inhibitors (B/2)
4Alisma plantago-aquaticaCommon Waterplantain5267
2 ItalyItaly 1994 Rice bensulfuron-methyl, and cinosulfuron 24 ALS inhibitors (B/2)
4Alisma plantago-aquaticaCommon Waterplantain1130
3 PortugalPortugal 1995 Rice bensulfuron-methyl 34 ALS inhibitors (B/2)
4Alisma plantago-aquaticaCommon Waterplantain169
4 SpainSpain 2000 Rice bensulfuron-methyl 38 ALS inhibitors (B/2)
4Alisma plantago-aquaticaCommon Waterplantain5138
5 TurkeyTurkey 2009 Rice azimsulfuron, bensulfuron-methyl, and penoxsulam 71 ALS inhibitors (B/2)
4Alisma plantago-aquaticaCommon Waterplantain5529
Literature about Similar Cases

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PERMISSION MUST BE OBTAINED FIRST if you intend to base a significant portion of a scientific paper on data derived from this site. Citation:
Heap, I.  The International Herbicide-Resistant Weed Database.  Online.  Saturday, April 10, 2021 .  Available Copyright © 1993- 2021 All rights reserved. Fair use of this material is encouraged. Proper citation is requested.