(Monochoria korsakowii)

ALS inhibitors (B/2)

China, Jilin
Mizuaoi (JPN)/Moolokzam (KOR) (Monochoria korsakowii) is a monocot weed in the Pontederiaceae family.  In China this weed first evolved resistance to Group B/2 herbicides in 2003 and infests Rice.   Group B/2 herbicides are known as ALS inhibitors (Inhibition of Acetolactate Synthase ).  Research has shown that these particular biotypes are resistant to bensulfuron-methyl, and pyrazosulfuron-ethyl and they may be cross-resistant to other Group B/2 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.

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QUIK STATS (last updated Jul 10, 2007 )

Common NameMizuaoi (JPN)/Moolokzam (KOR)
SpeciesMonochoria korsakowii
GroupALS inhibitors (B/2)
Herbicidesbensulfuron-methyl, and pyrazosulfuron-ethyl
LocationChina, Jilin
Contributors - (Alphabetically)Tae Seon Park 
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Confirmation Tests

Field, Greenhouse, and Laboratory trials comparing a known susceptible Mizuaoi (JPN)/Moolokzam (KOR) biotype with this Mizuaoi (JPN)/Moolokzam (KOR) biotype have been used to confirm resistance. For further information on the tests conducted please contact the local weed scientists that provided this information.

Genetic studies on Group B/2 resistant Mizuaoi (JPN)/Moolokzam (KOR) indicate that the inheritance is determined by a one gene, dominant, nuclear trait.  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 B/2 resistant Mizuaoi (JPN)/Moolokzam (KOR) from China 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

Researchers have indicated that Group B/2 resistant Mizuaoi (JPN)/Moolokzam (KOR) is ecologically less fit than normal susceptible Mizuaoi (JPN)/Moolokzam (KOR).  There may be a note below or an article discussing the fitness of this biotype in the Fact Sheets and Other Literature
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Physiology Of Herbicide Action
National Institute Of Agricultural Science And Technology
Department Of Crop Protection
Dept of Plant Sciences
51 Campus Dr.,
Suweon, 441-707
South Korea
Email Tae Seon Park


The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in China have been instrumental in providing you this information. Particular thanks is given to Tae Seon Park for providing detailed information.
Herbicide Resistant Mizuaoi (JPN)/Moolokzam (KOR) Globally
(Monochoria korsakowii)
Herbicide Resistant Mizuaoi (JPN)/Moolokzam (KOR) Globally
(Monochoria korsakowii)
Drag a column header and drop it here to group by that column
Herbicide Resistant Mizuaoi (JPN)/Moolokzam (KOR) Globally
(Monochoria korsakowii)
#CountryFirstYearSituationActive IngredientsSite of Action
1 ChinaChina 2003 Rice bensulfuron-methyl, and pyrazosulfuron-ethyl 9 ALS inhibitors (B/2)
118Monochoria korsakowiiMizuaoi (JPN)/Moolokzam (KOR)5302
2 JapanJapan 1994 Rice bensulfuron-methyl, imazosulfuron, and pyrazosulfuron-ethyl 25 ALS inhibitors (B/2)
118Monochoria korsakowiiMizuaoi (JPN)/Moolokzam (KOR)129
3 South KoreaSouth Korea 1998 Rice bensulfuron-methyl 27 ALS inhibitors (B/2)
118Monochoria korsakowiiMizuaoi (JPN)/Moolokzam (KOR)153
Literature about Similar Cases

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Heap, I.  The International Herbicide-Resistant Weed Database.  Online.  Saturday, April 17, 2021 .  Available Copyright © 1993- 2021 All rights reserved. Fair use of this material is encouraged. Proper citation is requested.