International Journal of Agriculture and Environmental Research™

ISSN 2455-6939


K. Coulibaly , I.B. Kebe1 ,J. Mpika1 , E. Kassin , A.A. Romain , W.P. N'Guessan , M.G. Tahi , S.B. Guiraud , M. Assi , B. Kone , K. F. N'Guessan , D. Kone

Black pod, caused by Phytophthora spp., is the most widespread and significant disease in Ivoirian cocoa plantations. However, the levels of yield losses related to the disease are poorly understood. In order to accurately determine the level of the disease in areas where abnormal yield losses have been reported, observations were made in cocoa plantations in the Sud Bandama, Moyen Comoe, Haut Sassandra, Bas Sassandra, Sud Comoe and Moyen Cavally regions. From this perspective, epidemic observations on-farm were made in 54 rural plantations selected in 9 localities located in 6 main cocoa producing regions. Each observation plot consisted of 100 trees randomly distributed in each cocoa plantation. In each plot, healthy ripe pods infected by black pod, Diplodia pod rot, gnawed pods as well as wilted (physiological drying of very young fruits) cherelles (young pods) were counted biweekly for three years. The results showed that yield losses due to black pod varied depending on the region. The Moyen Cavally region recorded the highest rate of losses (55.22%) compared to 11.44%, 28.84%, 24.44%, 27.04% and 37.25% recorded in the Sud Comoe, Bas Sassandra, Haut Sassandra, Moyen Comoe, and Sud Bandama, respectively. These high rates are similar to those recorded in countries where Phytophthora megakarya, a species known for its aggressiveness, is rampant. The epidemiological evolution in those regions showed that black pod attacks occur only during the rainy season. The epidemic phase in the Moyen Cavally stood out from the five other regions by its intensity and duration. The epidemic difference might be due to the progression of P. megakarya in this region bordering the new belt previously located in the northern area of Ivorian cocoa plantations. The new outbreak of black pod in that area requires a review of the two-zone subdivision of cocoa plantations, taking into account the structure and dynamics of Phytophthora spp populations. Knowledge of the distribution of the incidence as well as the epidemiological evolution in those regions will help develop a regionalized control strategy against black pod.

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