<b>HRAC Group 2</b> <font size='2'> (Legacy B) </font> resistant Tripleurospermum perforatum (=T. inodorum) from Denmark

INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 2 (LEGACY B) RESISTANT SCENTLESS CHAMOMILE
(Tripleurospermum perforatum (=T. inodorum))

Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)

Denmark

INTRODUCTION		SCENTLESS CHAMOMILE
Scentless Chamomile (Tripleurospermum perforatum (=T. inodorum)) is a dicot weed in the Asteraceae family. In Denmark this weed first evolved resistance to Group 2 (Legacy B) herbicides in 2010 and infests Spring Barley, and Winter wheat. 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 florasulam, iodosulfuron-methyl-Na, and tribenuron-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.

QUIK STATS (last updated May 07, 2017 )
Common Name	Scentless Chamomile
Species	Tripleurospermum perforatum (=T. inodorum)
Group	Inhibition of Acetolactate Synthase HRAC Group 2 (Legacy B)
Herbicides	florasulam, iodosulfuron-methyl-Na, and tribenuron-methyl
Location	Denmark
Year	2010
Situation(s)	Spring Barley, and Winter wheat
Contributors - (Alphabetically)	Solvejg Mathiassen
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NOTES ABOUT THIS BIOTYPE

GENERAL

Solvejg Mathiassen

April 2017 Update

Tripleurospermum perforatum

20 verified cases. Most of these cases are seed samples sent by farmers or consultants on suspicion of resistance. They have been tested in pot experiments including a susceptible and resistant reference population. Tribenuron-methyl and florasulam have been applied in 4-6 doses. A survey on untreated plots in agricultural fields all over Denmark showed that T. inodorum was resistant in 1% of the fields.

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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Scentless Chamomile biotype with this Scentless Chamomile 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 Scentless Chamomile 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 Scentless Chamomile from Denmark 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 Scentless Chamomile from Denmark please update the database.

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CONTRIBUTING WEED SCIENTISTS

SOLVEJG MATHIASSEN

Senior Scientist Aarhus University, Science and Technology Dept. of Agroecology P.o. Box 30 Slagelse, 4200, Slagelse Municipality Denmark Email Solvejg Mathiassen

ACKNOWLEDGEMENTS
The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Denmark have been instrumental in providing you this information. Particular thanks is given to Solvejg Mathiassen for providing detailed information.

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Herbicide Resistant Scentless Chamomile Globally
(Tripleurospermum perforatum (=T. inodorum))

Country

FirstYear

Situation

Active Ingredients

Site of Action

Czech Republic

2021

Wheat

florasulam, and tribenuron-methyl