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

International Survey of Herbicide-Resistant Weeds

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Thursday, November 21, 2024

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

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

United States, Kansas

INTRODUCTION		COMMON SUNFLOWER
Common Sunflower (Helianthus annuus) is a dicot weed in the Asteraceae family. In Kansas this weed first evolved resistance to Group 2 (Legacy B) herbicides in 1996 and infests Soybean. 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 Jan 01, 2014 )
Common Name	Common Sunflower
Species	Helianthus annuus
Group	Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicides	imazethapyr
Location	United States, Kansas
Year	1996
Situation(s)	Soybean
Contributors - (Alphabetically)	Kassim Al-Khatib, and Dallas Peterson
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NOTES ABOUT THIS BIOTYPE

AREAS FOUND

Kassim Al-Khatib

Eastern Kansas

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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse, and Laboratory 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 Kansas please update the database.

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CONTRIBUTING WEED SCIENTISTS

KASSIM AL-KHATIB

Director and Ce Specialist, Statewide IPM Program Statewide IPM Program Integrated Pest Management 2801 Second Street #152 Davis, 95618-7774, California United States Email Kassim Al-Khatib Web : Web Site Link

DALLAS PETERSON

Professor and Extension Weed Specialist Kansas State University Department of Agronomy 3703 Throckmorton Plant Sciences Center 1712 Claflin Road Manhattan, KS 66506-0110, Kansas United States Email Dallas Peterson Web : Web Site Link

ACKNOWLEDGEMENTS
The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Kansas have been instrumental in providing you this information. Particular thanks is given to Kassim Al-Khatib, and Dallas Peterson 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