Impact of plot maintenance and level of cocoa tree leaf cover on spread of Swollen shoot disease in Côte d'Ivoire: Case of Petit-Bondoukou site

Abstract

Swollen shoot is a viral disease of cocoa that is developing in the region of Soubré and is causing very serious damage. However, little is known about the epidemiological factors responsible for this disease, which makes it difficult to control the swollen shoot virus. The main objective of this study was to determine the influence of plot maintenance level and the leaf cover of tree on the prevalence of Swollen shoot disease at the site of Petit-Bondoukou. The observation system consists of a sentinel size 10 km X 10 km. Each sentinel site is made up of 16 clusters of 2.5 km X 2.5 km containing about 10 plots which constitute the different observation points. In this study, observations were made in 4 plots of the site. The variables measured during data collection were the number of trees affected by the swollen shoot, the leaf cover level of each test tree and the maintenance level of sampling plots. A descriptive analysis was carried out with the data in order to understand their dispersal. Comparative analysis of swollen shoot prevalence and leaf cover level using the one-way ANOVA showed a significant relationship. Comparison of swollen shoot prevalence and plot maintenance level using the Kruskall-Wallis test showed that the prevalence of swollen shoot disease did not depend on the maintenance level. However, the leaf cover level of the test trees influenced the prevalence of swollen shoot disease. This is justified by the fact that test trees with low or medium leaf cover had significantly higher prevalences of CSSV.