Leaf diseases, mainly, helmintosporiosis (Bipolaris spp.), anthracnose (Colletotrichum graminicola) and rust (Puccinia spp.), may cause reduction in maize yield. This study aimed to evaluate the occurrence and severity of helmintosporiosis, anthracnose and rust, as well as productivity of different genotypes of maize in response to increasing doses of nitrogen. Disease severity was evaluated using a score scale in nine maize genotypes (AG9040, AG7088, 30F35, 3F624, 1F583, 1F632, 1F557, 1F640 and ID219) subjected to four different nitrogen levels (67; 112; 157; and 202 kg ha-1) in two cropping years (2009/2010 and 2010/2011). To determine the productivity, it was used the weight of collected grains. It was observe that the severity of helmintosporiosis, anthracnose and rust varied in response to nitrogen levels and between the genotypes evaluated during two cropping years, although there was no clear relationship between the nitrogen levels applied and disease incidence in two cropping years. Rust was detect only during the cropping year I. Although the severity of foliar diseases, in general, these did not significantly affect the productivity of the maize genotypes evaluated. Of the evaluated genotypes, genotype AG7088 can be consider the most productive and the most resistant to the diseases evaluated.
helmintosporiosis; anthracnose; rust; Zea mays; nitrogen
