Chemical Management of Broadleaf Buttonweed and Brazilian Pusley in Different Application Methods

Abstract

Increased use of glyphosate in transgenic soybean areas has selected resistant and tolerant weed species. The aim of this study was to evaluate chemical management strategies for controlling Borreria latifolia and Richardia brasiliensis at pre-emergence (Pre), early post-emergence (Poste) and late post-emergence (Postl). Six experiments were carried out in a completely randomized design with four replicates per treatment in the Pre experiments and three in the Poste and Postl experiments, for each of the species. In the Pre experiments, tests were performed with herbicides imazethapyr, sulfentrazone, chlorimuron, diclosulam, S-metolachlor and saflufenacil. In the Poste experiments, seedlings were sprayed with herbicides bentazon, fomesafen, lactofen, flumioxazin and glyphosate. In Postl experiments, adult plants received glyphosate application associated with herbicides 2,4-D, carfentrazone, imazethapyr, flumiclorac, flumioxazin, sulfentrazone, chlorimuron, saflufenacil and glufosinate, plus three sequential applications with glyphosate only and paraquat/diuron. In the experiments, there was a control treatment without application of herbicides. In the Pre experiments, the plants established at 14 and 28 days after application (DAA) were evaluated. In the Poste and Postl experiments, shoot dry matter evaluation and visual control were performed at 14 and 28 DAA. The herbicides sulfentrazone, S-metolachlor and saflufenacil suppressed the emergence of both B. latifolia as R. brasiliensis; chlorimuron-ethyl and diclosulam were effective only on R. brasiliensis. In Poste, fomesafen, lactofen and flumioxazin reached levels of control over 90% of plants of both species. In Postl, glyphosate associated with carfentrazone, flumiclorac, flumioxazin, chlorimuron-ethyl, saflufenacil, glufosinate, and sequential applications of glyphosate/glyphosate, glyphosate/paraquat+diuron, glyphosate+2,4-D/paraquat+diuron reached levels control higher than 95%.

Eficácia de herbicidas no controle Spermacoce verticillata e seletividade para as plantas de milho

“…Os herbicidas saflufenacil e flumioxazina estiveram entre os mais eficazes ao longo de todas as avaliações, sem diferenças entre si e doses, com eficácia de até 98,8% aos 28 DAA. Esses resultados corroboram com outros estudos em que herbicidas inibidores da PROTOX foram eficazes no controle de plantas daninhas da família Rubiaceae (Jhala et al, 2012;Vitorino et al, 2012;Gallon et al, 2019;Carbonari et al, 2020), ou especificamente para S. verticillata para a aplicação de flumioxazina (Fadin et al, 2018). A aplicação de atrazina também proporcionou controle final no mesmo patamar dos mais eficazes, com 97% para a aplicação da dose 2.000 g i.a.…”

“…Neste contexto é importante a utilização de outros herbicidas além do glifosato no controle de S. verticillata, com destaque para herbicidas inibidores da protoporfirinogênio oxidase (PROTOX), como flumioxazina, ou inibidores da enzima acetolactato sintase (ALS) como cloransulam (Fadin et al, 2018). Também herbicidas utilizados no controle de outras espécies da família Rubiaceae podem vir a ser utilizados, com destaque para sulfentrazona, saflufenacil, lactofem (inibidores da PROTOX), S-metolacloro (inibidor da síntese de ácidos graxos de cadeia longa), 2,4-D (auxina sintética), glufosinato (inibidor da glutamina sintetase [GS]) (Gallon et al, 2019;Kalsing et al, 2020), entre outros.…”