
The dieback of reforested plantations is a pathology with various biotic and /or abiotic causes. In Cote d'Ivoire, this pathology affects Tectona grandis, Terminalia ivorensis and Terminalia superba in the reforestation plantation. The involvement of macroscopic and microscopic fungi has been studied to investigate the causes of the decline of these forest species. Assessments of land in classified forests of Irobo and Bouaflé and sampling of carpophores, roots, stems and soil were done. The fungi were isolated on standard Potato Dextrose Agar (PDA) and specific P5PARH media. Our results showed that the decline is more pronounced in the classified forest of Irobo (78.51%) than that of Bouafle and also showed a biotic kind of fungal disease. Various fungi have been identified, including pathogens (Fusarium, Cylindrocarpon, Verticillium, Cladosporium, Sclerotinia, Botryodiplodia, Pestalotia, Phytophthora, Phoma), parasites of weakness (Aspergillus, Penicillium and Fusarium) and hyperparasites (Trichoderma). The fungi differ from one site to another and between types of samples. Fungal species by their nature actively participate in this complex phenomenon feared for these reforestation silvicultural consequences.