International Survey of Herbicide-Resistant Weeds

Countries Weeds Herbicides Mutations Graphs References Researchers
GROUP B/2 RESISTANT SMALLFLOWER UMBRELLA SEDGE
(Cyperus difformis)


ALS inhibitors (B/2)

Greece, Thessaloniki - Northern Greece
INTRODUCTION SMALLFLOWER UMBRELLA SEDGE
Smallflower Umbrella Sedge (Cyperus difformis) is a monocot weed in the Cyperaceae family.  In Greece this weed first evolved resistance to Group B/2 herbicides in 2009 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 azimsulfuron, and halosulfuron-methyl 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 Oct 19, 2016 )

Common NameSmallflower Umbrella Sedge
SpeciesCyperus difformis
GroupALS inhibitors (B/2)
Herbicidesazimsulfuron, and halosulfuron-methyl
LocationGreece, Thessaloniki - Northern Greece
Year2009
Situation(s)Rice
Contributors - (Alphabetically)Ilias Eleftherohorinos, and Nikolaos Kaloumenos 
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NOTES ABOUT THIS BIOTYPE

MECHANISM

Ilias Eleftherohorinos

Molecular basis of Cyperus difformis cross-resistance to ALS-inhibiting herbicides

S. Ntoanidou, N. Kaloumenos, G. Diamantidis, P. Madesis, I. Eleftherohorinos

Pesticide Biochemistry and Physiology 127 (2016) 38–45

Applications of 64 times higher rates of azimsulfuron and halosulfuron-methyl failed to reduce by 50% growth of 10 putative resistant (R) Cyperus difformis (smallflower umbrella-sedge) populations collected from rice fields located in Northern Greece. However, the growth rate of the susceptible (S) population was reduced by 50% by 1/4 of the recommended rate of both herbicides. The als gene sequencing identified point mutations at Pro-197 position, leading to amino acid substitution by Ala or Ser of the ALS enzyme. The in vitro activity of the ALS enzyme indicated that the I50 values (herbicide concentration required for 50% reduction of the ALS activity) ranged from 10.7 to 55.5 μM azimsulfuron and from 6.7 to 50.6 μM halosulfuron-methyl, whereas the respective values for the S pop­ulation were 0.09 and 0.11 μM. These results strongly support that cross-resistance of 10 C. difformis populations was due to point mutations of the als gene, which resulted in a less-sensitive ALS enzyme. This study reports the presence of a 1240 bp intron in the C. difformis als gene with the Pro-197 point mutations near the splice junction.

 

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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 Group B/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 B/2 resistant Smallflower Umbrella Sedge from Greece 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 B/2 resistant Smallflower Umbrella Sedge from Greece please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

ILIAS ELEFTHEROHORINOS
University Of Thessaloniki
Laboratory Of Agronomy
4033 Kensington Pl
Ghessaloniki, 54006
Greece
Email Ilias Eleftherohorinos
NIKOLAOS KALOUMENOS
Aristotle University Of Thessaloniki
Department Of Agriculture
4033 Kensington Pl
Thessaloniki, 54006
Greece
Email Nikolaos Kaloumenos

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Greece have been instrumental in providing you this information. Particular thanks is given to Ilias Eleftherohorinos, and Nikolaos Kaloumenos for providing detailed information.
Herbicide Resistant Smallflower Umbrella Sedge Globally
(Cyperus difformis)
Herbicide Resistant Smallflower Umbrella Sedge Globally
(Cyperus difformis)
Drag a column header and drop it here to group by that column
Herbicide Resistant Smallflower Umbrella Sedge Globally
(Cyperus difformis)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Australia (New South Wales ) AustraliaNew South Wales 1994 Rice bensulfuron-methyl 1 ALS inhibitors (B/2)
71Cyperus difformisSmallflower Umbrella Sedge6
2 BrazilBrazil 2000 Rice cyclosulfamuron, and pyrazosulfuron-ethyl 5 ALS inhibitors (B/2)
71Cyperus difformisSmallflower Umbrella Sedge5118
3 GreeceGreece 2009 Rice azimsulfuron, and halosulfuron-methyl 19 ALS inhibitors (B/2)
71Cyperus difformisSmallflower Umbrella Sedge13051
4 ItalyItaly 1999 Rice azimsulfuron, bensulfuron-methyl, and cinosulfuron 24 ALS inhibitors (B/2)
71Cyperus difformisSmallflower Umbrella Sedge5155
5 South KoreaSouth Korea 2002 Rice azimsulfuron, bensulfuron-methyl, cinosulfuron, cyclosulfamuron, ethoxysulfuron, halosulfuron-methyl, imazosulfuron, and pyrazosulfuron-ethyl 27 ALS inhibitors (B/2)
71Cyperus difformisSmallflower Umbrella Sedge152
6 SpainSpain 2000 Rice bensulfuron-methyl, and penoxsulam 38 ALS inhibitors (B/2)
71Cyperus difformisSmallflower Umbrella Sedge5140
7 TurkeyTurkey 2010 Rice azimsulfuron, bensulfuron-methyl, bispyribac-sodium, and penoxsulam 71 ALS inhibitors (B/2)
71Cyperus difformisSmallflower Umbrella Sedge5532
8 United States (California) United StatesCalifornia1993 Rice bensulfuron-methyl 45 ALS inhibitors (B/2)
71Cyperus difformisSmallflower Umbrella Sedge391
9 United States (Arkansas) United StatesArkansas2010 Rice halosulfuron-methyl 45 ALS inhibitors (B/2)
71Cyperus difformisSmallflower Umbrella Sedge5562
10 United States (California) United StatesCalifornia2013 Rice propanil 45 PSII inhibitor (Ureas and amides) (C2/7)
71Cyperus difformisSmallflower Umbrella Sedge6739
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Cite this site as: Heap, I.  The International Survey of Herbicide Resistant Weeds.  Online.  Internet.  Friday, October 20, 2017 .  Available  www.weedscience.org
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