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Soils from four different cassava cropping fields (Aniansué 1, Aniansué 2, Dramanekro 1, Dramanekro 2) were analyzed to evaluate abundance and diversity of Arbuscular Mycorrhizal Fungi associated with cassava rhizosphere in Abengourou, East Côte d'Ivoire. It was shown that the soils in the cassava cropping fields were all acidic with low levels of available phosphorus (P). A total of 29 species belonging to six different genera (Acaulospora, Ambispora, Claroideoglomus, Gigaspora, Glomus and Scutellospora) were found at Aniansué 1, 28 species belonging to six different genera (Glomus, Claroideoglomus, Acaulospora, Ambispora, Gigaspora, Pacispora) were found at Aniansué 2, 30 species belonging to six different genera (Glomus, Acaulospora, Ambispora, Gigaspora, Pacispora, Scutellospora) were found at Dramanekro 1 and 27 species belonging to five different genera (Glomus, Acaulospora, Ambispora, Gigaspora, Scutellospora) were found at Dramanekro 2. The genus Glomus was dominant at each cassava cropping field. Spore densities were high, positively correlated with both soil pH and Mg 2+ , but negatively with available P. Trap culture revealed good infection potential for all soils. The frequencies of mycorrhizal roots were more than 93% for all field soils.

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RésuméLa sensibilité des nématodes aux perturbations des forêts a été étudiée à l'échelle du paysage dans la région d'Oumé. L'échantillonnage a été réalisé le long d'un gradient de perturbations du milieu, partant des forêts vers le domaine rural, en raison de six répétitions par habitat. Les résultats ont montré que les nématodes libres représentent 68 % du peuplement de nématodes.

Objectives: Integrated soil fertility management (ISFM) is essential for sustainable management of tropical soils. However, soil fertility management is able to affect plant susceptibility to pests and diseases. The study investigated impact of soil fertilization practices on maize pests and diseases during two identical and simultaneous trials setup in SouthWest Cote d'Ivoire. Methodology and Results: Experiments were laid out using complete randomized block designs with three replicates and four treatments: (1) control; (2) chemical fertilization; (3) fertilization with cattle manure; (4) association "maize + legume" combined with chemical fertilization. Overall, 22 insect species collected and two diseases (maize streak disease and curvularia leaf spots) observed at both sites. Only cattle manure clearly increased pest and disease damages. The use of cattle manure significantly increased leaf infestation rate and maize streak disease frequency at both sites. Similar impact of NPK and cattle manure was obtained on maize yields either in monocropping or in mix cropping. Conclusions and application of findings: This study clearly confirmed that ISFM is able to affect plant susceptibility to pests and diseases. Cattle manure attracted a diversity of insects of diverse functional groups such as airborne pests. These latter affected some plant parts; in this case, maize leaves which infestation rate significantly increased. This attraction for multitude insects may increase vector-borne diseases such as maize streak which frequency significantly increased at both sites. Consequently, despite the potential of cattle manure to increase maize yield, their use as organic fertilizer requires to take some precautions. So, the promotion of cattle manure as organic fertilizer in substitution of chemical fertilizer in tropical regions where it is available is encouraged. However, it should be converted into compost or pre-treated for optimal use in agriculture. Finally, mix cropping could be suggested for optimization of economic profit.

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