Côte d’Ivoire is the first world producer of cocoa beans and represents 42 % of the world offer. A current reduction of the production is due to numerous constraints and particularly, to diseases and vermin of cacao tree. Documentation dedicated to cacao tree’s enemies in the Centre-West region of Côte d’Ivoire is almost non-existent while this region is the second main cacao zone production. Our study aims to contribute to a better knowledge of the impact cacao tree’s enemies. Three sites of plantations were choosed because of their degraded sanitary state and their easy access for a better follow-up. In 25 squares of 4 m aside, after the floristic inventory, the degree of attack was evaluate by direct observation on each tree. 343 trees were observed and 8 enemies were identified. The strongest infestations are Brown rot, other mushrooms and Mosses (77 - 90%), Swollen shoot (> 50%) and Ants (> 50%). The Swollen shoot and the Brown rot which establish the most alarming enemies on the economic aspect are strongly favored by the proximity with other enemies. These results could serve as reference for control diseases in the cacao plantations and sustainable production.

The impact of plant developmental stage on resistance to rice yellow mottle virus was assessed with a virulent isolate of the virus RYMV. Tests were conducted under controlled conditions at Africa Rice research center. Seed of two rice cultivar were sown at regular intervals in order to produce plant at different age at 35, 49, 63, 77 and 91 days after sowing (DAS) corresponding respectively to the beginning of tillering, active tillering, the end of tillering, panicle initiation and flowering. The inoculum was prepared by grinding 60 g of rice yellow mottle virus infected leaves with 1000 ml of distilled water in a mortar washed with alcohol. The plants were inoculated manually by rubbing the leaves from the leaf base to the tip with fingers moistened with inoculum. Visual leaf chlorosis, chlorophyll (SPAD), virus content and yield reductions due to RYMV were evaluated. Result showed that the two rice cultivars Bouake 189 and CT9153-11-7-1-1 were more susceptible when inoculated at 35 and 49 days after sowing (DAS), attaining up with 99 % and 93% yield loss respectively for the two rice cultivar at 35 DAS. When inoculated at 63 DAS, these cultivar were observed to have developed partial resistance and became total resistance at 91 DAS attaining up 3% yield loss.