<b>HRAC Group 9</b> <font size='2'> (Legacy G) </font> resistant Helianthus annuus from United States, Texas

International Survey of Herbicide-Resistant Weeds

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Thursday, October 31, 2024

HRAC GROUP 9 (LEGACY G) RESISTANT COMMON SUNFLOWER
(Helianthus annuus)

Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)

United States, Texas

INTRODUCTION		COMMON SUNFLOWER
Common Sunflower (Helianthus annuus) is a dicot weed in the Asteraceae family. In Texas this weed first evolved resistance to Group 9 (Legacy G) herbicides in 2015 and infests Corn (maize). Group 9 (Legacy G) herbicides are known as Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (Inhibition of EPSP synthase). Research has shown that these particular biotypes are resistant to glyphosate and they may be cross-resistant to other Group 9 (Legacy G) 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 Feb 09, 2017 )
Common Name	Common Sunflower
Species	Helianthus annuus
Group	Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
Herbicides	glyphosate
Location	United States, Texas
Year	2015
Situation(s)	Corn (maize)
Contributors - (Alphabetically)	Muthukumar Bagavathiannan, and Josh McGinty
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ACADEMIC ASPECTS

Confirmation Tests

Field, and 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 9 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 9 (Legacy G) resistant Common Sunflower from Texas please update the database.

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CONTRIBUTING WEED SCIENTISTS

MUTHUKUMAR BAGAVATHIANNAN

Graduate Student The University Of Nottingham Plant Sciences College of Natural& Applied Sciences UOG Station, Western Pacific Tropical Research Center Loughborough, , LE12 5RD, Leicestershire United Kingdom Email Muthukumar Bagavathiannan

JOSH MCGINTY

Extension Agronomist Texas A&M Agrilife Extension Service Soil and Crop Sciences 10345 State Highway 44 Corpus Christi, 78406, Texas United States Email Josh McGinty Web : Web Site Link

ACKNOWLEDGEMENTS
The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Texas have been instrumental in providing you this information. Particular thanks is given to Muthukumar Bagavathiannan, and Josh McGinty 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