Oliveira Neto, Antonio Mendes, Constantin, Jamil, Silvério de Oliveira Júnior, Rubem, Guerra, Naiara, de Almeida Dan, Hugo, Marcos Silva Vilela, Lélio, Von Pinho Botelho, Lucas, and André Ávila, Lucas
This work aimed at evaluating the burndown efficiency of sequential applications of herbicides onConyza spp. in areas that remained in fallow during the winter, as well as at monitoring the residualeffect of herbicides in soil on weed control within soybean cycle. The experiment was carried outin a field where soybean was the previous summer crop and that remained non-cultivated duringthe winter. All herbicide treatments were composed by two burndown sequential applications: thefirst by spraying a tank mixture of glyphosate+2,4-D and the second by tank mixtures composed byglyphosate plus one or more herbicides with residual activity in the soil (chlorimuron-ethyl, flumioxazinand diclosulam). Evaluations included the burndown efficiency on emerged fleabane (plants ≥ 20cm and plants < 20 cm) and the residual effect of herbicides on the new fluxes of morningglory andsida. Soybean was sowed five days after the second burndown application. One single applicationof glyphosate+2,4-D was sufficient to control completely fleabane plants < 20 cm. For plants ≥20 cm,tank mixtures of glyphosate plus either chlorimuron-ethyl or diclosulam in the second applicationprevented the occurrence of fleabane regrowth, without however eliminate them. Treatmentscontaining herbicides with residual activity in soil (chlorimuron-ethyl, flumioxazin, chlorimuronethyl+flumioxazin and diclosulam) were in suppressing the development of morningglory and sida., O trabalho teve como objetivo avaliar a eficiência da dessecação de manejo com aplicaçãosequencial de herbicidas sobre o controle de Conyza spp. em áreas que permaneceram em pousiono inverno, bem como monitorar o efeito residual no solo dos herbicidas no controle de plantasdaninhas dentro do ciclo da cultura da soja. O experimento foi conduzido em área cultivadacom soja no verão e que permanecia em pousio durante o inverno. Foram avaliados tratamentoscompostos por duas aplicações sequenciais de dessecação de manejo: a primeira com a misturaem tanque de glyphosate+2,4-D e a segunda por misturas em tanque contendo glyphosate e umou mais herbicidas com atividade residual no solo (chlorimuron-ethyl, flumioxazin e diclosulam).Avaliou-se o efeito dos tratamentos no controle das plantas de buva com altura superior a ≥ 20 cm(20 a 40 cm) e plantas com altura menor a < 20 cm(3 a 19 cm) e o efeito residual dos herbicidassobre os novos fluxos de emergência de corda-de-viola e de guanxuma até o fechamento daentrelinha da soja. A semeadura da soja ocorreu cinco dias após a segunda aplicação sequencial.Uma única aplicação de glyphosate + 2,4-D foi suficiente para controlar a buva com altura inferiora 20 cm. Para plantas de buva maiores que 20 cm, a mistura de chlorimuron-ethyl ou diclosulamao glyphosate na segunda aplicação sequencial de manejo evitou a ocorrência de rebrotas,sem, contudo, eliminar as mesmas. Os tratamentos de manejo com atividade residual no solo(chlorimuron-ethyl, flumioxazin, chlorimuron-ethyl+flumioxazin e diclosulam) foram eficazes nasupressão do desenvolvimento de corda-de-viola e guanxuma durante o ciclo da cultura da soja. Burndown systems with residual activity for fallow areas infested with fleabaneAbstractThis work aimed at evaluating the burndown efficiency of sequential applications of herbicides onConyza spp. in areas that remained in fallow during the winter, as well as at monitoring the residualeffect of herbicides in soil on weed control within soybean cycle. The experiment was carried outin a field where soybean was the previous summer crop and that remained non-cultivated duringthe winter. All herbicide treatments were composed by two burndown sequential applications: thefirst by spraying a tank mixture of glyphosate+2,4-D and the second by tank mixtures composed byglyphosate plus one or more herbicides with residual activity in the soil (chlorimuron-ethyl, flumioxazinand diclosulam). Evaluations included the burndown efficiency on emerged fleabane (plants ≥ 20cm and plants < 20 cm) and the residual effect of herbicides on the new fluxes of morningglory andsida. Soybean was sowed five days after the second burndown application. One single applicationof glyphosate+2,4-D was sufficient to control completely fleabane plants < 20 cm. For plants ≥20 cm,tank mixtures of glyphosate plus either chlorimuron-ethyl or diclosulam in the second applicationprevented the occurrence of fleabane regrowth, without however eliminate them. Treatmentscontaining herbicides with residual activity in soil (chlorimuron-ethyl, flumioxazin, chlorimuronethyl+flumioxazin and diclosulam) were in suppressing the development of morningglory and sida.