INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 9 (LEGACY G) RESISTANT ARROCILLO
(Paspalum paniculatum)

Inhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)

Costa Rica, Limón, Alajuela
INTRODUCTION ARROCILLO
Arrocillo (Paspalum paniculatum) is a monocot weed in the Poaceae family.  In Costa Rica this weed first evolved resistance to Group 9 (Legacy G) herbicides in 2010 and infests Banana and Plantain, and Pejibaye palm.   Group 9 (Legacy G) herbicides are known as Inhibition of Enolpyruvyl Shikimate Phosphate Synthase (Inhibition of EPSP synthase).  Research has shown that these particular biotypes are resistant to glyphosate and they may be cross-resistant to other Group 9 (Legacy G) 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 Aug 31, 2017 )

Common NameArrocillo
SpeciesPaspalum paniculatum
GroupInhibition of Enolpyruvyl Shikimate Phosphate Synthase HRAC Group 9 (Legacy G)
Herbicidesglyphosate
LocationCosta Rica, Limón, Alajuela
Year2010
Situation(s)Banana and Plantain, and Pejibaye palm
Contributors - (Alphabetically)Bernal Valverde 
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ACADEMIC ASPECTS

Confirmation Tests

Greenhouse trials comparing a known susceptible Arrocillo biotype with this Arrocillo 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 9 resistant Arrocillo 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

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 9 (Legacy G) resistant Arrocillo from Costa Rica please update the database.
 
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CONTRIBUTING WEED SCIENTISTS

BERNAL VALVERDE
Honorary Associate Professor
The University of Copenhagen
Department of Plant and Environmental Sciences
Hojebakkegaard Allé 13
Taastrup, DK-2630, Hovedstaden
Denmark
Email Bernal Valverde

ACKNOWLEDGEMENTS

The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Costa Rica have been instrumental in providing you this information. Particular thanks is given to Bernal Valverde for providing detailed information.
Herbicide Resistant Arrocillo Globally
(Paspalum paniculatum)
Herbicide Resistant Arrocillo Globally
(Paspalum paniculatum)
Drag a column header and drop it here to group by that column
Herbicide Resistant Arrocillo Globally
(Paspalum paniculatum)
#CountryFirstYearSituationActive IngredientsSite of Action
1 Costa RicaCosta Rica 2010 Banana and Plantain, and Pejibaye palm glyphosate 11 Inhibition of Enolpyruvyl Shikimate Phosphate Synthase ( HRAC Group 9 (Legacy G)
 		335Paspalum paniculatumArrocillo17101
Literature about Similar Cases

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HRAC Global Heap, I.  The International Herbicide-Resistant Weed Database.  Online.  Sunday, October 18, 2026.  Available at  www.weedscience.org

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