Com o objetivo de avaliar a eficiência de fungicidas no controle das principais doenças do arroz irrigado, foram instalados três ensaios em delineamento de blocos casualizados, no municÃpio de Formoso do Araguaia - Tocantins. Os resultados do Ensaio número 1 (cultivar Epagri 108) mostram que todos os tratamentos reduziram a severidade de mancha-parda, porém, apenas os tratamentos com Miclobutanil-113g e 150g diferiram da testemunha. Com relação à mancha dos grãos, os tratamentos com Miclobutanil-113g, 125g, 138g e 150g obtiveram diferença estatÃstica da testemunha. No Ensaio número 2 (cultivar Jaçanã), verificou-se que os tratamentos não tiveram efeito no controle da mancha-parda e brusone das panÃculas. Com relação à mancha dos grãos, apenas os tratamentos Epoxiconazole + Piraclostrobina, Phthalide 200g + Tebuconazole 100g e Tebuconazole foram estatisticamente diferentes da testemunha. No Ensaio número 3 (cultivar Epagri 109), os tratamentos mais eficazes para o controle da brusone das panÃculas foram Phthalide, na dose de 300g i.a./ha e Phthalide 300g + Tebuconazole 100g. Os tratamentos Epoxiconazole + Piraclostrobina e Phthalide 300 + Tebuconazole 100g reduziram significativamente a severidade de mancha-parda nas folhas. Os tratamentos Epoxiconazole + Piraclostrobina, seguido de Phthalide nas doses de 300g i.a/ha e 400g e Tebuconazole diferiram estatisticamente para o controle da mancha dos grãos. Melhores produtividades foram alcançadas pelos tratamentos com Phthalide na dose de 300 g i.a./ha, Epoxiconazole + Piraclostrobina, Phthalide 300g + Tebuconazole 100g e Phthalide 200g + Tebuconazole 100g. Durante a condução dos ensaios verificou-se que as variáveis climáticas favoreceram o desenvolvimento das doenças.
To evaluate the efficiency of fungicides in the control of the main irrigated rice diseases and productivity, as well, three experiments were settled in a completely randomized block design at Formoso do Araguaia – State of Tocantins. Although the results of the experiment 1 (Epagri 108 cultivar) have showed that brown spot severity decreased in all treatments, only Myclobutanil-113 and 150g significantly differed from the controls. When grain spots control was evaluated, the treatments composed of Myclobutanil-113g, 125g, 138g and 150g significantly differed from the controls. On the experiment 2 (Jaçanã cultivar), the treatments did not show any effect on the control of brown spot and panicle blast. When grain spot was evaluated, only the treatments Epoxiconazole + Pyraclostrobina, Fthalide 200g + 100g Tebuconazole and Tebuconazole, significantly differed from the controls. When the Epagri 109 cultivar was used (experiment 3), the most effective treatments, for panicle blast control, were Phthalide, at the rate of 300 g i.a./ha and Phthalide 300g + Tebuconazole 100g. The treatments Epoxiconazole + Pyraclostrobina and Phthalide 300 + Tebuconazole 100g significantly reduced brown spot severity on the leaves. The treatments Epoxiconazole + Pyraclostrobina, followed by Phthalide at the rates of 300g i.a/ha and 400g and Tebuconazole significantly differed on grain spot control. The highest yielding was obtained on the treatments where Phthalide was applied at the rate of 300 g i.a./ha, Epoxiconazole + Pyraclostrobina, Phthalide 300g + Tebuconazole 100g and Phthalide 200g + Tebuconazole 100g. Over the whole experimental period it was observed that climate conditions have favored diseases development.
