INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 2 (LEGACY B) RESISTANT CALIFORNIA ARROWHEAD
(Sagittaria montevidensis)


Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

Australia, New South Wales
INTRODUCTION CALIFORNIA ARROWHEAD
California Arrowhead (Sagittaria montevidensis) is a monocot weed in the Alismataceae family.  In New South Wales this weed first evolved resistance to Group 2 (Legacy B) herbicides in 1994 and infests Rice.   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 bensulfuron-methyl 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 Jun 06, 2004 )

Common NameCalifornia Arrowhead
SpeciesSagittaria montevidensis
GroupInhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicidesbensulfuron-methyl
LocationAustralia, New South Wales
Year1994
Situation(s)Rice
Contributors - (Alphabetically)Jim Pratley 
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NOTES ABOUT THIS BIOTYPE

AREAS FOUND

Jim Pratley
Irrigation areas of southern NSW.

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GENERAL

Jim Pratley
Little scope for chemical control of Arrowhead after bensulfuron is gone.

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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible California Arrowhead biotype with this California Arrowhead biotype have been used to confirm resistance. For further information on the tests conducted please contact the local weed scientists that provided this information.
 
Genetics

Genetic studies on HRAC Group 2 resistant California Arrowhead 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 California Arrowhead from New South Wales please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

JIM PRATLEY
Dean, Faculty Of Science & Agriculture
Charles Sturt University
School Of Agriculture
Dept of Crop& Soil Sciences
PO Box 646420,
Wagga Wagga, 2678, New South Wales
Australia
Email Jim Pratley

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in New South Wales have been instrumental in providing you this information. Particular thanks is given to Jim Pratley for providing detailed information.
Herbicide Resistant California Arrowhead Globally
(Sagittaria montevidensis)
Herbicide Resistant California Arrowhead Globally
(Sagittaria montevidensis)
Drag a column header and drop it here to group by that column
Herbicide Resistant California Arrowhead Globally
(Sagittaria montevidensis)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Australia (New South Wales ) AustraliaNew South Wales 1994 Rice bensulfuron-methyl 1 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
146Sagittaria montevidensisCalifornia Arrowhead7
2 BrazilBrazil 1999 Rice bispyribac-sodium, cyclosulfamuron, ethoxysulfuron, metsulfuron-methyl, and pyrazosulfuron-ethyl 5 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
146Sagittaria montevidensisCalifornia Arrowhead1179
3 BrazilBrazil 2009 Rice bentazon, bispyribac-sodium, ethoxysulfuron, imazethapyr, metsulfuron-methyl, penoxsulam, and pyrazosulfuron-ethyl 5 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)
146Sagittaria montevidensisCalifornia Arrowhead5588
4 BrazilBrazil 2023 Rice florpyrauxifen 5 Auxin Mimics ( HRAC Group 4 (Legacy O)
146Sagittaria montevidensisCalifornia Arrowhead26264
5 ChinaChina 2003 Rice bensulfuron-methyl, and pyrazosulfuron-ethyl 9 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
146Sagittaria montevidensisCalifornia Arrowhead5303
6 United States (California) United StatesCalifornia1993 Rice bensulfuron-methyl 45 Inhibition of Acetolactate Synthase ( HRAC Group 2 (Legacy B)
146Sagittaria montevidensisCalifornia Arrowhead390
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