Performance de herbicidas para o controle de plantas daninhas no sorgo

Abstract

Resumo -O controle químico de plantas daninhas na cultura do sorgo é limitado pela baixa quantidade de herbicidas registrados para a cultura. Estudos sobre os efeitos e eficácia dos herbicidas na cultura do sorgo são fundamentais para aumento de alternativas para o controle da comunidade infestante. A partir deste contexto, o presente trabalho teve como objetivo avaliar o efeito de intoxicação provocado pelos herbicidas na cultura do sorgo, bem como a eficácia destes para o controle de plantas daninhas. O experimento foi realizado a campo no delineamento em blocos casualizados, avaliando-se oito tratamentos com quatro repetições. Os tratamentos foram constituídos por três herbicidas aplicados em pré-emergência (g ha -1 ): trifluralin (1200), Smetolachlor (768) e clomazone (1000); quatro tratamentos com herbicidas aplicados em pós-emergência: bentazon (720), bentazon + atrazine (480 + 880), atrazine (2200) e bentazon + pendimethalin (720 + 1000); além de uma testemunha sem herbicida (com plantas daninhas). Os herbicidas aplicados em pré-emergência (clomazone, trifluralin e S-metolachlor) causaram elevada intoxicação às plantas de sorgo. Não foram constatadas injúrias nas plantas de sorgo pela utilização dos herbicidas em pós-emergência. Os herbicidas clomazone e trifluralin apresentaram controle para todas as plantas daninhas monocotiledôneas avaliadas, entretanto o S-metolachlor somente não obteve controle para C. echinatus. O uso de atrazine ou a sua mistura com bentazon se mostrou promissores para controle de plantas daninhas dicotiledôneas. Palavras-chaves: controle químico; dicotiledôneas; monocotiledôneas; intoxicação Abstract -Chemical weed control in sorghum crop is limited by the low quantity of herbicides registered for the crop. Studies on the effects and effectiveness of herbicides in sorghum crop are essential to increase alternatives for the control of weeds. In this context, the present study was to evaluate the effect of intoxication caused by herbicides in sorghum, as well as the effectiveness of these for weed control. The experiment was conducted the field in a randomized block design, evaluating eight treatments with four replications. The treatments consisted of three herbicides 1 Recebido para publicação em 27/05/2016 e aceito em 24/09/2016. 2 Mestre em Produção Vegetal pela Universidade de Rio Verde, Rio Verde, GO, Brasil.

Herbicide Selectivity in Preemergence of Sweet Sorghum Cultivated in Different Soil Texture

“…For treatments with S-metolachlor ( 960and 720 g ha -1 ), trifuralin (1000 g ha -1 ), [atrazine 25 According to Karam et al (2002), the reduction in the symptoms of intoxication generated by the presence of the safener occurs with the increase in the detoxification of the herbicide due to the increase in enzymatic activity. Machado et al (2016) found that in the applications of trifluralin (1200 g ha -1 ), S-metolachlor (768 g ha -1 ) and clomazone (1000 g ha -1 ) in preemergence of sorghum, in clay soil, maximum levels of 53.3% of phytointoxication were found, however, the evaluations were carried out only until 21 DAE, that is, one week less when compared to our study.…”

Selectivity and Effectiveness of Herbicides in the Grain Sorghum Crop

“…However, even at lower concentrations (1,440 g a.i. ha -1 ), S-metolachlor can be absorbed by the shoot of sorghum plants, causing intoxication and reducing growth and yield, as observed in this study and by Machado et al (2016) at a dose of 768 g a.i. ha -1 or also higher doses of the product (2,520 g a.i.…”

“…Competition with weed at this stage is quite critical, and if control measures are not taken in the first few weeks after the emergence of sorghum plants, grain yield can be reduced by around 35-70% (Rodrigues et al, 2010) The chemical control of weeds in the crop is limited by the low amount of registered herbicides, being only atrazine, simazine and 2,4-D (Correia and Gomes, 2015;AGROFIT, 2018). Studies on the effects and efficacy of herbicides on sorghum are fundamental to increase alternatives for weed control (Machado et al, 2016).…”

Comparison of Different Weedicides on Multi-cut Sorghum Sudan Grass Hybrid for Productivity Enhancement and Control of Grassy Weeds

“…Limited chemical eradication of weeds in sorghum is due to the reason that Atrazine, Simazine and 2,4-D are the only registered herbicides (Correia and Gomes, 2015). It is essential to investigate the efficacy and residual effects of different herbicides while searching for alternatives of weeds control (Machado et al, 2016). Atrazine is mainly considered to eradicate dicotyledons having low eradication range on grasses.…”