BIOLOGY AND HARMFULNESS OF INVASIVE DISCOSCOREA IN SUGARCANE (SACHARUM OFFICINARUM L.) CULVITATION IN THE AREA OF THE SUGAR REFINERY COMPLEX OF FERKESEDOUGOU IN NORTH COTE D’IVOIRE

*Author for Correspondence Floristic sampling done in hundred plots around the sugar refinery complex of Ferke 1 and Ferke 2 located in Ferkessedougou in North Cote d’Ivoire during the cropping cycle of 2011-2012, revealed 30 species of weed including 6 of invasive Discoreas as D. bulbifera, D. dumetorum, D. hirtiflora, D. lecardi,. paraehensillis and D. preussii. Observations done on the biology, the phenology and the harmfulness showed that the occurrence of invasive Dioscorea in sugarcane fields was effective by bulbils and in certain level by tubers and bulbils generating new tubers, when produced during the vegetative growth stage between the second and seventh months of cultivation. D. bulbifera, D. dumetorum, D. hirtiflora and D. lecardi were producer of bulbils and occurred in highest potential densities. Excepted for D. lecardi, they were more harmful to sugarcane plant because of overlapping of vegetative cycle durations likewise for D. praehensilis. Hence, these weeds may have high competiveness ability with the crop for soil water and nutrient uptake as well as for sun light reception. Key Words: Weed, Dioscorea, Sugarcane, Biology, Phenology and Harmfulnes

FLORA OF THE INSELBERGS MAFA-MAFOU AND BRAFOUEBY AND THEIR PIEDMONTS (SOUTH-EASTERN OF CÔTE D’IVOIRE)

*Author for Correspondence This study relates to the characterization of the flora of two inselbergs (Brafouéby and Mafa-Mafou) located at Sikensi and Adzopé, in forest zone of Côte d'Ivoire. The inventories floristic carried out made it possible to draw up a floristic list made up of 389 species, 290 genus and 88 families. The importance of the families on the inselbergs depends on the surrounding matrix. The study of the biological spectra revealed the clear predominance of the phanérophytes of which the density believes the top downwards. The analysis of the phytogeographical spectra highlighted abundance and the predominance of the bases element of guineo-congolese. The proportions of the species with broad distribution and those of connection decrease of the top downwards. In addition, the number of species guineo-congoleses believes of the top downwards