<b>HRAC Group 1</b> <font size='2'> (Legacy A) </font> resistant Urochloa plantaginea (=Brachiaria plantaginea) from Brazil

INTERNATIONAL HERBICIDE-RESISTANT WEED DATABASE

HRAC GROUP 1 (LEGACY A) RESISTANT ALEXANDERGRASS
(Urochloa plantaginea (=Brachiaria plantaginea))

Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)

Brazil, Paraná

INTRODUCTION		ALEXANDERGRASS
Alexandergrass (Urochloa plantaginea (=Brachiaria plantaginea)) is a monocot weed in the Poaceae family. In Brazil this weed first evolved resistance to Group 1 (Legacy A) herbicides in 1997 and infests Soybean. Group 1 (Legacy A) herbicides are known as Inhibition of Acetyl CoA Carboxylase (Inhibition of Acetyl CoA Carboxylase ). Research has shown that these particular biotypes are resistant to butroxydim, diclofop-methyl, fenoxaprop-ethyl, fluazifop-butyl, haloxyfop-methyl, propaquizafop, quizalofop-ethyl, and sethoxydim and they may be cross-resistant to other Group 1 (Legacy A) 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 Jan 07, 2001 )
Common Name	Alexandergrass
Species	Urochloa plantaginea (=Brachiaria plantaginea)
Group	Inhibition of Acetyl CoA Carboxylase HRAC Group 1 (Legacy A)
Herbicides	butroxydim, diclofop-methyl, fenoxaprop-ethyl, fluazifop-butyl, haloxyfop-methyl, propaquizafop, quizalofop-ethyl, and sethoxydim
Location	Brazil, Paraná
Year	1997
Situation(s)	Soybean
Contributors - (Alphabetically)	Marcio Adoryan, Pedro Christoffoleti, Marluce Cortez, Gerson Gelmini, Maria Novo, Ricardo Victória, and Ribas Vidal
Edit this Case \| Add New Case of Resistance \| Add Note

NOTES ABOUT THIS BIOTYPE

AREAS FOUND

Ribas Vidal

Guarapuava and Mangueiqinha

Edit this Note | Add New Note

ACADEMIC ASPECTS

Confirmation Tests

Field, Greenhouse, and Laboratory trials comparing a known susceptible Alexandergrass biotype with this Alexandergrass 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 1 resistant Alexandergrass indicate that the inheritance is determined by a 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 1 (Legacy A) resistant Alexandergrass from Brazil 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 1 (Legacy A) resistant Alexandergrass from Brazil please update the database.

Edit Case | Add Note | Add Article | Add New Case |

CONTRIBUTING WEED SCIENTISTS

MARCIO ADORYAN

Agronomic Solutions Brazil Bayer Cropscience Field Solutions Rod. Doutor Roberto Moreira 5005 – EAE - CEAT Paulinia, 13148-914, São Paulo Brazil Email Marcio Adoryan

PEDRO CHRISTOFFOLETI

Associate Professor III Universidade de Sao Paulo Crop Science Department ESALQ - USP - LPV - Av. Padua Dias 11 - C. Postal 09 Piracicaba, 13418-900, São Paulo Brazil Email Pedro Christoffoleti Web : Web Site Link

MARLUCE CORTEZ

Weed Scientist University Of South Brazil Crop Science Department 2788 Waterpointe Cr Piracicaba, 13418-900, São Paulo Brazil Email Marluce Cortez Web : Web Site Link

GERSON GELMINI

Weed Scientist University Of South Brazil Crop Science Department 945 Marion Street Piracicaba, 13418-900, São Paulo Brazil Email Gerson Gelmini Web : Web Site Link

MARIA NOVO

Weed Scientist University Of South Brazil Crop Science Department Department of Crop& Soil Sciences 115 Coastal Way, PO Box 748 Piracicaba, 13418-900, São Paulo Brazil Email Maria Novo Web : Web Site Link

RICARDO VICTÓRIA

Weed Scientist University Of South Brazil Crop Science Department Dept of Plant Sciences Piracicaba, 13418-900, São Paulo Brazil Email Ricardo Victória Web : Web Site Link

RIBAS VIDAL

Professor Universidade Federal Do Rio Grande Do Sul Plant Sciences Rod. Carlos João Strass Acesso Orlando, Cx Postal 231, Porto Alegre, CEP 91001-970, RS Brazil Email Ribas Vidal Web : Web Site Link

ACKNOWLEDGEMENTS
The Herbicide Resistance Action Committee, The Weed Science Society of America, and weed scientists in Brazil have been instrumental in providing you this information. Particular thanks is given to Marcio Adoryan, Pedro Christoffoleti, Marluce Cortez, Gerson Gelmini, Maria Novo, Ricardo Victória, and Ribas Vidal for providing detailed information.

Drag a column header and drop it here to group by that column

Herbicide Resistant Alexandergrass Globally
(Urochloa plantaginea (=Brachiaria plantaginea))

Country

FirstYear

Situation

Active Ingredients

Site of Action

Brazil

1997

Soybean

butroxydim, diclofop-methyl, fenoxaprop-ethyl, fluazifop-butyl, haloxyfop-methyl, propaquizafop, quizalofop-ethyl, and sethoxydim

Inhibition of Acetyl CoA Carboxylase ( HRAC Group 1 (Legacy A)

Literature about Similar Cases

Page size:

select

Page: of 1

Items 1 to 1 of 1

Voll, E. ; Gazziero, D. L. P. ; Brighenti, A. M. ; Adegas, F. S. ; Gaudêncio, C. de A. ; Voll, C. E.. 2008. Weed plants: the seed bank and the sustainability of the technology of soyabean cropping. Documentos - Embrapa Soja : .

Knowledge of weed seed banks is an important factor in soyabean cropping and weed management in Brazil. This document discusses various aspects of the importance of the seed bank. The first part of the document discusses the biological cycle of the seed bank and interactions between the weed species, environmental factors (climate and soil) and competition with the crop, and crop and soil management in relation to the weed seed bank. The major weed species of soyabeans in the seed bank are Euphorbia heterophylla, Bidens pilosa, Commelina sp., Brachiaria plantaginea [Urochloa plantaginea], Digitaria spp., and Cardiospermum halicacabum. The next part of the document looks at factors in the emergence of weeds, including the weed species, the sowing date of the crop, the use of herbicides, the effect of vegetative cover, the effect of soil fertility. The last part of the document discusses the weed seed bank in relation to its effects on competition with the crop/crop cultivar, weed herbicide resistance, the effect of using genetically modified soyabeans, integrated management systems, organic farming, and preharvest desiccation of soyabeans with herbicides (in extreme situations only)..

Page size:

select

Page: of 1

Items 1 to 1 of 1

PERMISSION MUST BE OBTAINED FIRST if you intend to base a significant portion of a scientific paper on data derived from this site. Citation:
Heap, I. The International Herbicide-Resistant Weed Database. Online. Friday, October 31, 2025 . Available www.weedscience.org Copyright © 1993- 2025 WeedScience.org All rights reserved. Fair use of this material is encouraged. Proper citation is requested.