Efficacy of herbicides applied to Digitaria horizontalis plants under different water conditions

Abstract

This project aimed to relate the control efficiency of ACCase inhibiting herbicides applied post-emergence to Digitaria horizontalis plants under different soil water contents. The experiments were conducted in a greenhouse, with the application of three different herbicides (fluazifop-p-butyl, haloxyfop-methyl, and sethoxydim + mineral oil Assist). The experimental design used for each herbicide was completely randomized, with four replications, consisting of a 3 x 4 factorial, with the combination of water management strategies (-0.03, -0.07 and -1.5 MPa) and four doses of these products (100%, 50%, 25%, and 0% of the recommended dose). Herbicide application was made at two vegetative stages, 4-6 leaves and 2-3 tillers. The visual phytotoxicity evaluations were performed at 14 days after application and the plant dry weight at the end of the study was evaluated. The control efficiency was not affected by water management strategies when applied to the recommended dose of the herbicides in early stages of plant development (4-6 leaf stage). In late applications (2-3 tiller stage) the plants held under drought stress showed less phytotoxicity.

Herbicidas inibidores da accase em plantas de Cenchrus echinatus em estresse hídrico

“…Em aplicações tardias (2-3 perfilhos) o manejo hídrico influenciou a eficiência dos herbicidas sobre plantas de Digitaria horizontalis, pois as cultivadas sob estresse hídrico apresentaram menor fitotoxicidade (PEREIRA et al, 2012b). Estes resultados foram coerentes com a literatura que relata que normalmente há redução do desempenho do herbicida nas plantas sob estresse hídrico (BOYDSTON, 1992;PEREIRA et al, 2010;PEREIRA et al, 2012a).…”

Eficacia de herbicidas posemergentes sobre Oryza latifolia Desv. (arroz pato) y selectividad al arroz Palmar 18

“…Koeler, que requirió una dosis de 184 g i.a. ha -1 para obtener un 99 % de control (Pereira et al, 2012).…”

“…Keywords: weeds, selectivity, phytotoxicity, phenological stages, variety. para el control de poáceas en varios cultivos dicotiledóneos (Neal, 2016), evaluado en arroz (Griffin & Baker, 1990;Pereira et al, 2012;Valverde et al, 2000) e incluso reportado su efecto sobre arroz rojo (Noldin et al, 1998); sin embargo, su uso fue sustituido por otros herbicidas más selectivos al arroz, tales como profoxidim, cihalofop-butil, quinclorac y clomazone (Esqueda Esquivel & Tosquy Valle, 2014;Márquez, 2002), de los cuales, los últimos tres no son eficaces para el control de arroz maleza.…”