<b>HRAC Group 2</b> <font size='2'> (Legacy B) </font> resistant Helianthus annuus from United States, South Dakota

INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 2 (LEGACY B) RESISTANT COMMON SUNFLOWER
(Helianthus annuus)

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

United States, South Dakota

INTRODUCTION		COMMON SUNFLOWER
Common Sunflower (Helianthus annuus) is a dicot weed in the Asteraceae family. In South Dakota this weed first evolved resistance to Group 2 (Legacy B) herbicides in 1996 and infests Cropland. 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.

QUIK STATS (last updated Sep 15, 2000 )
Common Name	Common Sunflower
Species	Helianthus annuus
Group	Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicides	imazethapyr
Location	United States, South Dakota
Year	1996
Situation(s)	Cropland
Contributors - (Alphabetically)	Leon Wrage : retired
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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Common Sunflower biotype with this Common Sunflower 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 Common Sunflower 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 Common Sunflower from South Dakota please update the database.

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CONTRIBUTING WEED SCIENTISTS

LEON WRAGE : RETIRED

Extension Emeritus South Dakota State University Agriculture Plant Science-Box 2140C Brookings, 57007, South Dakota United States Email Leon Wrage : retired Web : Web Site Link

ACKNOWLEDGEMENTS
The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in South Dakota have been instrumental in providing you this information. Particular thanks is given to Leon Wrage : retired for providing detailed information.

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Herbicide Resistant Common Sunflower Globally
(Helianthus annuus)

Country

FirstYear

Situation

Active Ingredients

Site of Action

France

2009

Sunflower

imazamox, and tribenuron-methyl