Temporal analysis of brown eye spot of coffee and its response to the interaction of irrigation with phosphorous levels

Abstract

Brown eye spot (BES—Cercospora coffeicola) is a major disease of coffee, and its occurrence is affected by water supply and nutritional balance. Little is known about the effect of phosphorous (P) on coffee fields under irrigation. Thus, this study evaluated the effect of the interaction between different water application levels and phosphorus levels (5 irrigation levels × 4 phosphorus levels) on the intensity of this disease. The area under the incidence progress curve (AUIPC) was calculated and subjected to analysis of variance. The progress curve of the average incidence of BES varied in both evaluation years. In Year 1 (November 2011 to December 2012), the incidence peaked on August 12, 2012 (22.45%), while in Year 2 (January 2013 to January 2014), the incidence reached its highest level on September 12, 2013 (16.29%). The exponential nonlinear model was adjusted for the two years. There was an interaction between irrigation and phosphorus levels on October 07, 2012. The incidence interacted significantly with the harvest dates. On the first evaluation date, an increase in phosphorus levels at shallower irrigation depths and an absence of phosphate fertilizer at higher irrigation levels caused higher incidences.