Integrated Production (IP) can provide the growing demand for quality fruit, food safety, environmental protection, and product traceability. In IP, fertilization practices and disease control are viewed as being closely related. However, this linkage has been mostly ignored and few studies are available concerning the 'shot hole' phytopathogen (Wilsonomyces carpophilus) in plum (Prunus salicina). In this paper, the incidence and severity of this disease were investigated by using combined doses of nitrogen and potassium fertilizer in a commercial plum orchard, cv Reubennel in Araucária (PR). The treatments consisted of combinations of five doses of nitrogen (40, 80, 120, 160 and 200kg ha-1year-1) and two doses of potassium rates (55 and 110kg ha-1year-1). The incidence and severity of "shot hole" disease were evaluated at 20 days intervals during the period of November/2004 to March/2005, and once during October/2006. The first harvest´s data were integrated in time to produce the area under the disease progress curve (AUDPC) of the incidence and severity and all data were analyzed statistically using generalized linear models in longitudinal data theory. The disease severity was higher in the second year of the study with the maxima being 0.70 and 2.25 in the first and second year, respectively. The incidence and severity was highest in 160 and 200kg nitrogen ha-1year-1 treatments. Potassium does not interfere in the incidence and severity of the disease due to the high content found in the soil and plant.
Prunus salicina; plum; nutrition; Wilsonomyces carpophilus; epidemiology; integrated production
