Herbicide Resistant Weeds

GROUP B/2 RESISTANT ARROWLEAFED MONOCHORIA (Monochoria vaginalis)
South Korea

Saturday, July 31, 2010

What's on this page

Arrowleafed Monochoria

1.	Introduction
2.	Level of Infestation
3.	Quick Statistics
4.	Notes about this biotype
5.	Academic Aspects
6.	R Arrowleafed Monochoria Globally
7.	Fact Sheets and Literature
8.	Contributing Weed Scientists
9.	Acknowledgements
10.	Where to now?

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Introduction

Level of Infestation

Arrowleafed Monochoria (Monochoria vaginalis) is a monocot weed in the Pontederiaceae family. In South Korea this weed first evolved resistance to Group B/2 herbicides in 1999 and infests rice. Group B/2 herbicides are known as ALS inhibitors (Inhibition of acetolactate synthase ALS (acetohydroxyacid synthase AHAS)). Research has shown that these particular biotypes are resistant to bensulfuron-methyl and they may be cross-resistant to other Group B/2 herbicides.

Local weed scientists estimate that Group B/2 resistant Arrowleafed Monochoria in South Korea infests 6-10 sites and the number of sites are increasing. They also estimate that there are 11-50 acres infested with Group B/2 resistant Arrowleafed Monochoria and the area infested is increasing.

The 'Group' letters/numbers that you see throughout this web site refer to the classification of herbicides by their mode of action. To see a full list of herbicides and HRAC herbicide classifications click here.

QUIK STATS ( last updated Mar 05, 2001 )
Common Name	Arrowleafed Monochoria
Species	Monochoria vaginalis
Group	ALS inhibitors (B/2)
Herbicides	bensulfuron-methyl
Location	South Korea
Year	1999
Situation(s)	rice
Sites	6-10
Acres Infested	11-50
Contributors	TAE SEON PARK
Input Data	Edit this Case \| Add New Case of Resistance \| Add Note

ACADEMIC ASPECTS

Confirmation Tests

Field, and Greenhouse trials comparing a known susceptible Arrowleafed Monochoria biotype with this Arrowleafed Monochoria 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

The genetic basis of resistance for this biotype is either unknown or has not been entered in the database. If you know anything about the genetic inheritance of this biotype please update the database.

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 B/2 resistant Arrowleafed Monochoria from South Korea please update the database.

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HERBICIDE RESISTANT ARROWLEAFED MONOCHORIA GLOBALLY
#	Country	Year	Sites	Acres	Mode of Action
1.	South Korea	1999	6-10	11-50	ALS inhibitors (B/2)

FACT SHEETS AND OTHER LITERATURE	Format
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Scientific Abstracts on Herbicide Resistant Monochoria vaginalis
A mutation confers Monochoria vaginalis resistance to sulfonylureas that target acetolactate synthase.
Wang, G., Y. Lin, W. Li, M. Ito, and K. Itoh. 2004. A mutation confers Monochoria vaginalis resistance to sulfonylureas that target acetolactate synthase. Pesticide Biochemistry and Physiology. 80: 43-46.
Occurrence of resistant weeds to sulfonylurea herbicides in Japan.
Miyahara, M., J. Guh O., and D. Lee J. 1998. Occurrence of resistant weeds to sulfonylurea herbicides in Japan. Korean Journal of Weed Science. 18: 268-279.

CONTRIBUTING WEED SCIENTISTS

TAE SEON PARK	Edit
Physiology of Herbicide Action NATIONAL INSTITUTE OF AGRICULTURAL SCIENCE AND TECHNOLOGY DEPARTMENT OF CROP PROTECTION SEODUNDONG KWEONSEONKU SUWEON 249 KOREA SUWEON, 441-707 South Korea Email TAE SEON PARK

Acknowledgements

Where to now?

The Herbicide Resistance Action Committee, the Weed Science Society of America, and weed scientists in South Korea have been instrumental in providing you this information. Particular thanks is given to TAE SEON PARK for providing detailed information.

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