Response of Three Chloris elata Populations to Herbicides Sprayed in Pre- and Post-Emergence

Abstract

In agricultural areas of Brazil, where there is no establishment of cover crops in the off-season and in fruit orchards, an increase in Chloris elata infestations, syn. Chloris polydactyla, has been observed. With the purpose to evaluate the response of three populations (Itaberaí - GO, Matão - SP e Jaboticabal - SP) of C. elata to herbicides sprayed before and after emergence, four experiments were conducted. In the first one, the differential tolerance of three C. elata populations to the herbicide glyphosate (0, 0.18, 0.36, 0.72, 0.96, 1.44, 2.88, 5.76 and 11.52 kg a.e. ha-1) was studied. In the other experiments, the control of the three populations by herbicides applied in pre-emergence (clomazone, diclosulam, flumioxazin, isoxaflutole, chlorimuron-ethyl, metribuzin, S-metolachlor, sulfentrazone and trifluralin) or in post-emergence (clethodim, fenoxaprop-p-ethyl, fluazifop-p-butyl, haloxyfop-methyl, quizalofop-p-tefuryl, mesotrione, nicosulfuron, tembotrione, glufosinate-ammonium, paraquat and glyphosate) was evaluated. The population from Jaboticabal was more susceptible to glyphosate than Itaberaí and Matão, at smaller doses. In pre-emergence, clomazone, isoxaflutole, metribuzin, S-metolachlor and trifluralin were effective in controlling the three populations. The same results were observed for clethodim, fenoxaprop, fluazifop, haloxyfop, quizalofop, paraquat and glyphosate, when sprayed on plants with 2-6 tillers. C. elata populations differed for the herbicides flumioxazin, chlorimuron-ethyl and nicosulfutron.

Tumble windmill grass (Chloris verticillata Nutt.) control with POST herbicides

“…The least control (41 to 51%) was observed with imazamox and nicosulfuron. These results were consistent with Correia and Resende (2018), who previously reported only 27-66% control of C. elata with nicosulfuron. Similarly, Ferguson et al (2019) reported only 53% control of Chloris spp.…”

“…The least shoot dry biomass reduction of tumble windmill grass was observed with imazamox (43%). These findings are consistent with Correia and Resende (2018), who previously reported > 95% shoot biomass reduction of C. elata at 45 DAT with clethodim, quizalofop, and glyphosate applied at 2-3 tillers stage. In that same study, 47 to 73% shoot biomass reduction of C. elata was observed with nicosulfuron (Correia & Resende, 2018).…”

“…(2005), who previously reported complete control of tumble windmill grass with QPE and clethodim when applied at the seedling growth stage (2 to 4 inches tall). Similarly, Correia and Resende (2018) also reported >95% control of C. elata at 45 DAT with clethodim and quizalofop applied at 2–3 tillers stage. Glyphosate provided 89% control of tumble windmill grass (Table 4).…”

Potencial alelopático de extratos de Chloris gayana na germinação de soja e picão-preto

“…Entretanto, no Brasil embora tenha sido introduzida como planta forrageira, pesquisas evidenciaram o alto potencial de infestação e dano econômico da espécie em cultivos anuais de grão, com propagação via sementes (30.000 planta -1 ) e rizomas (CARVALHO et al, 2005), sendo considerada uma planta daninha atualmente, com redução de até 80% sobre a produtividade de grãos na cultura da soja (RASOOL et al, 2017). Recentemente, casos de resistência à molécula herbicida glifosato, inibidor da enzima enolpyruvylshikimato-3 fosfato (EPSPs) foram evidenciados, com dificuldade de controle em áreas infestadas (BRUNHARO et al, 2016;CORREIA;RESENDE, 2018).…”

Mixtures between glyphosate formulations and ACCase-inhibiting herbicides in the control of Chloris elata

“…Other species of this genus, such as C. barbata (7), C. virgata (20), C. truncata (19), and C. distichophylla (30) are also reported as resistant. In the last years, these species have gained importance in different crops, mainly grains and sugarcane, thus increasing the number of studies on their biology and management (2,3,9,12,13,25). In addition, no specific recommendations of glyphosate as chemical control of C. elata are available (4).…”