Seasonal Variation on the Incidence and Severity of Major Foliar Diseases of Cassava in Sierra Leone

Abstract

A diagnostic survey was conducted in the rainy and dry seasons from 2014 to 2015 to determine the incidence and severity of major diseases of cassava in Sierra Leone. At least three chiefdoms and five villages per district were targeted. The survey was carried out in fourteen districts of the country with geo references using a GPS. On the spot assessment was conducted in all fields. Prevalence, severity and incidence were calculated. The most dominant diseases included the cassava mosaic disease and the cassava bacterial blight. The prevalence of cassava mosaic disease was high with 69.1% and 61.5% in the rainy season and dry season, respectively. The prevalence of cassava bacterial blight was 100% and 92% in the rainy season and dry season, respectively. Diseases of less importance included white spot and brown spot diseases as well as cassava anthracnose disease. The study provides bases for the deployment of improved varieties and provides information on the seasonal prevalence, incidence and severity of cassava diseases in Sierra Leone.