The influence of nitrogen fertilization on the incidenceof brown spot (Helminthosporium oryzae Breda de Hann) on leavesof rice cultivar IAC 47 was studied under upland conditions. Theexperimental area was fertilized with 60 kg/ha P2O5, 30 kg/haK2O and 0, 15, 30, 45 and 60 kg/ha of N, in the form of ammoniumsulfate. Increase in nitrogen levels from 0 to 45 kg/ha decreased thenumber of lesions per leaf. A further increase to 60 kg/hA of Nincreased the lesion number.Estudou-se o efeito da fertilização nitrogenada sobre a incidência de mancha-parda (Helminthosporium oryzae Breda de Hann) nas folhas de arroz (Oryzae sativa L.) de sequeiro, da cultivar IAC 47, em solos de cerrado. Foram usados 60 kg/ha de P2O5, 30 kg/ha de K2O e zero, 15, 30, 45 e 60 kg/ha de N, na forma de sulfato de amônio. O aumento dos níveis de N, de zero a 45 kg/ha diminuiu o número de lesões por folha. O aumento de N para 60 kg/ha resultou em tendência de aumento do número de lesões.The influence of nitrogen fertilization on the incidence of brown spot (Helminthosporium oryzae Breda de Haan) on leaves of rice cultivar IAC 47 was studied under upland conditions. The experimental area was fertilized with 60 kg/ha P2O5, 30 kg/ha K20 and 0, 15, 30, 45 and 60 kg/ha of N. in the form of ammonium sulfate. Increase in nitrogen levels from 0 to 45 kg/ha decreased the number of lesions per leaf. A further Increase to 60 kg/ha of N increased the lesion number
