Management Programs to Control Conyza spp. in Pre-Soybean Sowing Applications

Abstract

The goal of this study was to compare the efficacy of different weed management through a burndown application followed by sequential applications of herbicides to control Conyza spp. Thus, four field experiments were conducted, two in the western region of Paraná state (E1 and E2), one in Jataí, Goiás state (E3) and another one in Ibirubá, Rio Grande do Sul state (E4). Conyza spp. in this area had a height ranging between 25 and 60 cm. Treatments were arranged in a randomized block design with four replications. The primary herbicide treatments were 2,4-D + glyphosate + diclosulam, chlorimuron-ethyl + glyphosate + 2,4-D, and four doses of diclosulam + halauxifen-methyl + glyphosate. These treatments were applied singly or in sequential applications, made 10 days before the application of ammonium glufosinate, paraquat or saflufenacil. In all experiments, results showed efficient (90%) control of treatments containing diclosulam + halauxifen-methyl in combination with glyphosate on day 35 DAA, regardless of sequential applications. Applications of 2,4-D + glyphosate + diclosulam or chlorimuron-ethyl + glyphosate + 2,4-D were not effective against Conyza spp. at E1 and E2 locations, possibly due to the greater weed size (50 to 60 cm) at these sites. However, the same treatments were effective at E3 and E4 locations, where weeds were smaller. Diclosulam + halauxifen-methyl + glyphosate associated with ammonium glufosinate, paraquat or saflufenacil in sequential applications, proved to be an important tool to manage Conyza spp. at different growth stages.

Control of Conyza spp. with sequential application of glufosinate in soybean pre-sowing

“…Other studies have also reported the efficacy of glufosinate in different chemical management programs in controlling Conyza spp. (MONTGOMERY et al, 2017;TAHMASEBI et al, 2018;ZOBIOLE et al, 2018). In addition to these results, other studies reported the efficacy of glufosinate in different management programs in controlling other weeds, for example Amaranthus palmeri (MANUCHEHRI et al, 2017), Sorghum halepense (LANDRY et al, 2016), Digitaria sanguinalis (AULAKH & JHALA, 2015) and Digitaria insularis (MELO et al, 2012;GEMELLI et al, 2013).…”

“…In addition, the use of pre-emergence and burndown herbicides at tank-mixed before sowing soybeans for effective management of C. sumatrensis resistant to paraquat. Among the burndown herbicides can be highlighted the glufosinate (MONTGOMERY et al, 2017;ZOBIOLE et al, 2018). While, other studies highlighted the efficacy of herbicides with preemergent action in controlling Conyza spp.…”

Estratégias de controle de Conyza spp. em pré-plantio da soja: Aplicações únicas ou sequenciais?

“…Em trabalho realizado por Brustolin et al (2020) aplicando a associação glifosato + sulfentrazona + diuron (1080 + 262-525 g ha -1 ) aos 42 dias após a aplicação dos tratamentos, obtiveram controle de 92% de Conyza spp, os autores ainda relatam que a aplicação isolada de sulfentrazona + diuron (262-525 g ha -1 ) resultaram em controle insatisfatório, com porcentagens inferiores a 80%. Zobiole et al (2018), trabalhando estratégias de controle de Conyza spp., com aplicação (diclosulam + halauxifen-metil) + glifosato (para dose de diclosulan partir de 23 g i.a. ha -1 ) com sequencial de amônioglufosinato (366 g i.a.…”

Germinação De Sementes De Capim Amargoso (Digitaria Insularis) Na Presença De Herbicidas Residuais

“…Dentre as diversas espécies de plantas daninhas, tanto monocotiledôneas quanto eudicotiledôneas, que infestam as lavouras de grãos, algumas têm se destacado pela sua grande plasticidade ecológica, o que amplia sua esfera de infestação, pela velocidade e hábito de crescimento, pela dificuldade de controle químico e adaptação ao sistema de plantio direto, que corresponde a cerca de metade da área cultivada com grãos no Brasil e, ainda, mais predominante na Região Centro Oeste e Estado de Goiás (ZOBIOLE et al, 2018;GUIMARÃES et al, 2019).…”

“…(buvas), Chloris elata (capim branco) e Digitaria spp. (capins colchão) e, destacadamente, Digitaria insularis (capim amargoso) vêm ampliando, tanto sua área, quanto seus níveis de infestação (TROPALDI et al, 2017;CORREIA;RESENDE, 2018;ZOBIOLE et al, 2018).…”