Seasonal Variation on Incidence and Severity of Cassava Bacterial Blight Disease in Sierra Leone

Abstract

A diagnostic survey was conducted in the rainy and dry seasons of 2014 and 2015 to determine the incidence and severity of major diseases of cassava in Sierra Leone. Five villages were targeted from three chiefdoms per district covering the entire country. Samples were collected with a hand-held GPS using a pre-determined gridded base map on a 1:50,000 scale. On-the-spot assessment of the prevalence, severity and incidence of major diseases of cassava was undertaken and spatial variability of incidence and severity of major diseases was mapped using ArcGIS 10.1 software. The study revealed that the cassava bacterial blight disease is emerging diseases of importance in Sierra Leone.  Prevalence of cassava bacterial blight disease was 100% and 92% in the rainy season and dry season respectively. The study provides information on seasonal prevalence incidence and severity of cassava bacterial blight disease as well as bases for the deployment of improved varieties that are resistant in areas most vulnerable to the diseases in Sierra Leone.