Bacterial wilt in potato (Solanum tuberosum) is caused by Ralstonia solanacearum in the highlands of Fouta Djalon in Guinea. The disease causes 50-70% loss of potato in Guinea. The bacterium is transmitted either by imported tuber seeds or through seed exchanges between the farmers themselves from a contaminated area to bacteria-free areas or through irrigation waters along the fields. This is mainly a consequence of the informal potato seed system that prevails in Guinea. Because of the high price of seeds, farmers use several sources of supply. However, potato is an attractive cash crop in Guinea and the most important economic crop in Fouta Djalon. Most populations in the middle Guinea utilizes potato. The potato farmer's organization in Guinea, FPFD (Fédération des Producteurs du Fouta Djalon), is a model in West African sub-region because of its dynamism and organization with its 500 groups, 25 unions and more than 25,000 members. Training of potato growers in certified seed production techniques remains a major problem in Guinea that needed to be solved. This information is important for developing bacterial wilt disease management strategies through the training of farmers and state support for research.

The present study aimed at evaluating the antifungal activities of NECO, ASTOUN and FERCA fungicides based of plants essentials oils against Phytophthora katsurae a major constraint in coconut plantations in Côte d'Ivoire. In vitro, the inhibition properties of these fungicides was evaluated at different concentrations 50, 100, 250, 500, 1000, 1500, 2000 and 2500 ppm and compared to a synthetic fungicide (phosphorous acid) at 1, 5, 10, 25, 50, 100 and 150 ppm on the radial growth of the mycelium of an isolated pathogen from a diseased nut. The mycelial growth was measured every day during 10 days in the Petri dishes. The results showed inhibition rates ranging from 1.48% to 100%. The biopesticides NECO and ASTOUN were effective against Phytophthora katsurae at respectively 149.14 and 272.38 ppm compared to phosphorous acid. NECO was fungitoxic at 2500 ppm and fungistatic at 1500 and 2000 ppm. Phosphorous acid was simply fungicidal at 150 ppm. Based on these results, these fungicides based of plants essentials oils could be used as biological control of Pnhytophthora katsurae in coconut plantations in Côte d'Ivoire.

Influence of root-knot nematodes of the genus Meloidogyne spp. on the growth and production of ten cultivars of tomato (Solanum lycopersicum L.