Health Map of Tuberous Root Rot of Cassava (Manihot Esculenta Crantz) in High Production Areas Cote D'ivoire

Abstract

Root rot of cassava tubers, Manihot esculenta Crantz, has become a scourge that devastates plantations and limits production in Côte d'Ivoire. The aim of this study was to investigate the distribution of cassava root rot on the one hand, and to assess the incidence and severity of varieties. The study was carried out in 13 localities where cassava is widely grown and 320 plots were observed and assessed. Symptoms were described by examining the above-ground and below-ground parts of the plants and described on the basis of existing information. In each plot visited, incidence and severity were noted. The disease is visible in the aerial part of the plant in two forms: leaf chlorosis and stem dieback. The disease is highly prevalent in the plots visited, with an incidence of between 25% and 100%, indicated by the colors pink, green and red. Analysis of the data collected showed that average incidence in the localities surveyed ranged from 10 to 56 %. In terms of disease severity, the results showed that all infected plots were severely attacked, with severity indices ranging from 2.50 to 4. Of the twenty-one cassava varieties found in the surveyed localities, the incidence recorded varied according to variety and type of varietal association. This threat is borne out by our results, which show that all cassava varieties encountered in the localities surveyed, more than 9 varieties are highly susceptible and attacked, with average incidences ranging from 40 to 100 %, regardless of the variety grown.