- Aerobic mesophilic, Black Sigatoka, Cropping systems, Libanga Likale,Yangambi 5Km, Litete, Gros Michel, Mycosphaerellafijiensis Morelet, Bacillus.
The microorganisms play crucial roles in the cycle of matter and damage the organic substances, sources of electrons, source of carbon, and source of energy for their biosynthesis. In this work, we studied the impact of the aerobic mesophiles microorganisms on the black sigatokaof banana in the old secondary forest. The objective was to count and to identify the microbial diversity of the forest ecosystems, as well as to study their impact on the development of the black sigatoka of banana. The assessment of the microbial populations has been done in an experimental field according to a device in blocks of Fischer by the method of successive dilutions of coloration of Gram and by the discharge of ascospores. The results showed that the rain season was lower in total microbial biomass (700, 7 colonies) than subdry season (840,3 colonies). The Bacillus genera have been more represented more than the Coccusgenera. The impact of black sigatoka of banana was raised at the cultivar LibangaLikale (40%) and low at Yangambi 5 Km (14%). The distribution of microorganisms in depth in the sub-dry season to the level of surface with vegetation was considerable either 3819, 3. 103 UFC( UNIT FORMAT COLONY) by gram of soil between 0 and 5 cm against 2754,5.103 UFC by gram of soil between 15 and 20 cm. This suggests that the raised number of microorganisms could have positive impact on soil fertility by decreasing the illnesses in this ecosystem.