<b>HRAC Group 2</b> <font size='2'> (Legacy B) </font> resistant Cyperus difformis from India

INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 2 (LEGACY B) RESISTANT SMALLFLOWER UMBRELLA SEDGE
(Cyperus difformis)

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

India, Chhattisgarh and Kerala states

INTRODUCTION		SMALLFLOWER UMBRELLA SEDGE
Smallflower Umbrella Sedge (Cyperus difformis) is a monocot weed in the Cyperaceae family. In India this weed first evolved resistance to Group 2 (Legacy B) herbicides in 2017 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 bispyribac-sodium 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 Mar 14, 2022 )
Common Name	Smallflower Umbrella Sedge
Species	Cyperus difformis
Group	Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicides	bispyribac-sodium
Location	India, Chhattisgarh and Kerala states
Year	2017
Situation(s)	Rice
Contributors - (Alphabetically)	V. K. Choudhary, Bhumesh Kumar, and Seshadri Reddy
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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse, and Laboratory trials comparing a known susceptible Smallflower Umbrella Sedge biotype with this Smallflower Umbrella Sedge 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 Smallflower Umbrella Sedge 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

Studies on the mechanism of resistance of Group 2 (Legacy B) resistant Smallflower Umbrella Sedge from India indicate that resistance is due to an altered target site. There may be a note below or an article discussing the mechanism of resistance in the Fact Sheets and Other Literature

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 Smallflower Umbrella Sedge from India please update the database.

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CONTRIBUTING WEED SCIENTISTS

V. K. CHOUDHARY

Senior Scientist ICAR-Directorate of Weed Research Agronomy ICAR-Directorate of Weed Research Maharajpur Jabalpur, 482004, Madhya Pradesh India Email V. K. Choudhary

BHUMESH KUMAR

Senior Scientist (plant Physiology) Directorate Of Weed Science Research Weed Biology And Physiology Dwsr, Maharajpur Adartal Jabalpur (mp) Jabalpur, 482004, MP India Email Bhumesh Kumar

SESHADRI REDDY

Weed Scientist Corteva Agriscience Weed Biology And Physiology 9330 Zionsville Rd Indianapolis, 46268, Indiana United States Email Seshadri Reddy

ACKNOWLEDGEMENTS
The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in India have been instrumental in providing you this information. Particular thanks is given to V. K. Choudhary, Bhumesh Kumar, and Seshadri Reddy for providing detailed information.

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Herbicide Resistant Smallflower Umbrella Sedge Globally
(Cyperus difformis)

Country

FirstYear

Situation

Active Ingredients

Site of Action

Australia (New South Wales )

1994

Rice

bensulfuron-methyl