With the introduction of an integrated production of peaches (PI) in Paraná, some modifications during the handling of this culture were necessary, in order to adapt it to the regional conditions. The Nitrogen fertilizer was recommended to PI from Rio Grande do Sul and it stated a maximum of 80 kg/ha of nitrogen (N) annually, becoming a limiting factor to the high productivity reached by some producers in the State of Parana. On the other hand, the increasing of the nitrogen dosage may favor a major incidence of leave and branch diseases, damaging the development of the plants. The present work aimed to evaluate the effect of nitrogen fertilizer in the production and in three diseases, cultivated in the PI system. An experiment in Lapa was carried through with the Chimarrita Cultivar, with three treatments (40, 80 and 160 kg/ha of N) and six repetitions. The production was evaluated counting the number of total fruits for useful plant in the harvest. For evaluation of the diseases the number was determined by the number of lesions (cankers) of Botryosphaeria dothidea in a marked plant of each fragment, two years in a row (2003 and 2004), in the period after flowering, shot hole (Wilsonomyces carpophilus) was determined by the incidence of the disease in the year of 2002 and to rust (Tranzschelia discolor) it was evaluated the incidence and severity in 2003 and 2004. With the data of the rust severity the progress curve of the disease and the fall of the leaves index in the period were obtained. In the third year it was observed that in the dose of 160 kg/ha of N the number of fruits was significant and bigger than in the other treatments. It was observed the growth of the incidence of cankers among the years, however without significant result for the different dosages of nitrogen. The shot hole also was not influenced by the treatments. The area below the progress curve of the diseases (AACPD) for rust severity was 20,7 % superior to the minor dose in relation to the major dose of nitrogen, however without any reflexes over the fall of the leaves index.
Peach; nitrogen; shot role; rust e canker
