Herbicide selectivity and weed control in cowpea

Authors

  • José Roberto Antoniol Fontes Embrapa Amazônia Ocidental
  • Inocencio Junior Oliveira Embrapa Amazônia Ocidental
  • Ronaldo Ribeiro Morais Embrapa Amazônia Ocidental

DOI:

https://doi.org/10.18227/1982-8470ragro.v13i0.5414

Keywords:

Vigna unguiculata. Weeds. Chemical control. Phytotoxicity.

Abstract

Weeds negatively affect cowpea plants, causing reduced growth, delayed development and yield loss. The aim of this study was to assay selectivity and effectiveness of weed control herbicides in cowpea cropping field conditions. For selectivity evaluation, the herbicide S-metolachlor, was used pre-emergence (PRE), and carfentrazone-ethyl, clethodim, fenoxaprop-p-ethyl, fluazifop-p-butyl and quizalofop-p-ethyl post-emergence (POST). In effectiveness evaluation, S-metolachlor (PRE), and carfentrazone-ethyl (POST), S-metolachlor in PRE and fluazifop-p-butyl (POST), clethodim, carfentrazone-ethyl and clethodim, fenoxapropp-ethyl, carfentrazone-ethyl and fenoxaprop-p-ethyl, fluazifop-p-butyl, carfentrazone-ethyl and fluazifop-pbutyl, quizalofop-p-ethyl and carfentrazone-ethyl and quizalofop-p-ethyl (POST). Two controls were included, one with weeding at 15 and 35 days after sowing (DAS) and the other without weed control. Carfentrazone-ethyl caused mild phytotoxicity in plants seven days after application, but did not reduce yield (2337 kg ha-1). The levels of weed control and productivity obtained with S-metolachlor alone or in association with carfentrazoneethyl or fluazifop-p-butyl, associated or not with carfentrazone-ethyl, were similar to those obtained with weeds. Spraying with carfentrazone-ethyl alone resulted in low control effectiveness and reduced yield (1511 kg ha-1). Weed interference during the crop cycle reduced yield by 77% (531 kg ha-1). The selectivity and effectiveness obtained with the herbicides should be considered as an agronomic and economically-viable.

Author Biographies

José Roberto Antoniol Fontes, Embrapa Amazônia Ocidental

Engenheiro Agrônomo, Mestre e Doutor em Fitotecnia - Universidade Federal de Viçosa, pesquisador da Embrapa Amazônia Ocidental, Matologia.

Inocencio Junior Oliveira, Embrapa Amazônia Ocidental

Pesquisador em Genética e Melhoramento de Plantas da Empresa Brasileira de Pesquisa Agropecuária (Embrapa), lotado na Embrapa Amazônia Ocidental, Manaus, AM.

Ronaldo Ribeiro Morais, Embrapa Amazônia Ocidental

Pesquisador em Ecofisiologia Vegetal da Empresa Brasileira de Pesquisa Agropecuária (Embrapa), lotado na Embrapa Amazônia Ocidental, Manaus, AM.

Published

23/07/2019

Issue

Section

Original Scientific Article