A Survey Methodology for Assessing Yield Potential and Coffee Berry Losses in Peasant Coffee

Abstract

SUMMARYThe effects of coffee berry disease (CBD) on yield are usually estimated by counting infected berries on marked branches throughout fruit development. This method is impractical when surveys are required of yield losses over large areas of extensively cultivated peasant coffee. A survey method is described for estimating yield potentials and the loss in yields due to severe CBD infection under such conditions. The method exploits the relation between numbers of flowering nodes and yield per tree, and requires a single subjective estimate of disease incidence on young expanding berries. Yield losses are estimated from the changes in this relation resulting from berry infection. Results are presented for peasant coffee at different stages of rehabilitation in Ethiopia. They indicate that the method is suitable for estimating.production in agronomic improvement projects and for identifying areas where CBD incidence might economically justify fungicide spraying.