Isolement des mocroorganismes impliques dans la pourriture des racines tubereuses du manioc (Manihot esculenta Crantz) au Gabon

Abstract

Soft and dry root rot are mainly found in cassava. Dry root rot is present in Gabon and in other African countries, but few related studies have been carried out on in Gabon. This article is specially focusing on Haut-Ogooué province sheds some light on both form of rot, with high prevalence of dry rot. The inventory of microorganisms found on the affected plants and tubers revealed the presence of fungi, with Penicillium (47.9 %) and Cladosporium (39.6 %), as prevailing genders, and bacteria, particularly thermotolerant coliforms. The most prevailing bacterial genders were Enterobacter (28.6 %), Klebsiella (16.9 %) and Bacillus (15.6 %). The disease developed preferentially in forest-savanna and forest transition areas. In forest areas, dry rot prevailed (80 %) even though it was also encountered in savanna regions in lower proportions. Soft rot is weakly present in forest, but totally absent in savannas.

Keywords: Manihot esculenta, microorganisms, dry rot, soft rot, ecosystem.

Agronomie Africaine 24 (3) : 171 - 181 (2012)