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Differential susceptibility of biotypes of conyza sumatrensis to Chlorimuron-ethyl herbicide

Authors :
Leandro Vargas
T. Dal Magro
Franciele Mariani
Pedro Jacob Christoffoleti
Dirceu Agostinetto
Filipe Martins Santos
IFRS Sertão
LEANDRO VARGAS, CNPT
USP - ESALQ
UFPel
UCS.
Source :
Planta Daninha, Vol 32, Iss 2, Pp 427-435 (2014), Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA-Alice), Empresa Brasileira de Pesquisa Agropecuária (Embrapa), instacron:EMBRAPA, Planta Daninha v.32 n.2 2014, Planta daninha, Sociedade Brasileira da Ciência das Plantas Daninhas (SBCPD), instacron:SBCPD
Publication Year :
2014
Publisher :
Sociedade Brasileira da Ciência das Plantas Daninhas, 2014.

Abstract

Horseweed (Conyza spp.) is an annual weed, infesting soybean crops in southern Brazil, with chlorimuron-ethyl being one of the most commonly used herbicides for its control. However, in recent soybean harvests, an unsatisfactory control of this weed using this herbicide was observed, generating suspicion regarding the selection of resistant biotypes. The objective of this study was to evaluate the susceptibility of horseweed biotypes to the herbicide chlorimuron-ethyl. Two experiments were conducted in a greenhouse; in the first one, the biotypes were selected selected, and the second experiment was arranged in a 5 x 5 factorial in a completely randomized design with four replications. The treatments used in the preparation of the dose response curves were doses of the herbicide chlorimuron-ethyl (0.0, 1.56, 3.13, 6.25, 12.5, and 25 g ha-1), applied on the five horseweed biotypes at the 3-4 leaf growth stage. The variables evaluated were visual control percentage and shoot dry weight, compared to the control without herbicide application, and plant acetolactate accumulation. It was concluded that there is a differential susceptibility among the biotypes at doses of less than 20 g ha-1 (dose response curves), which indicates low-level resistance. The practical consequences are the indications of chlorimuron-ethyl application at the maximum doses recomended and that the practice of rotating mechanisms of action must be used in the chemical weed management of these areas.

Details

Language :
English
ISSN :
01008358
Volume :
32
Issue :
2
Database :
OpenAIRE
Journal :
Planta Daninha
Accession number :
edsair.doi.dedup.....29880610719e5998d2b6a145992497eb