Caracterisation D’isolats Locaux De Metarhizium Spp, Champignon Entomopathogene De Cosmopolites Sordidus Germar, Isoles Des Bananeraies En Cote d’Ivoire

Abstract

Chemical insecticides have been commonly used against the black weevil, Cosmopolites sordidus, in banana plantations which caused huge economic and agricultural losses. Despite their benefits, pesticides can be hazardous to both humans and the environment. Intensive research in substituting chemical insecticides with biological control agents have been driven. The biological and molecular characteristics of ten strains of Metarhizium spp, isolated from dead weevils, collected in banana plantation in Côte d'Ivoire were studied. The study aims to identify the species of Metarhizium sp. The biological and molecular characteristics namely: length and width of the spores, colour of aerial mycelium as well as its variation over time, colour on the setback of the box, production of the diffusible pigment and the analysis of the region ITS (Internal Transcribed Spacer) were evaluated. The colonies presented at first a flat white mycelium cottony or fluffy appearance on which the spores formed small islets. After 21 days of incubation at 32°C. in the dark, the mycelium takes on the periphery a greenish coloration with a powdery appearance. The relief is fairly flat. The spores are ellipsoid in shape of 3 μm in length and 1 μm. The amplification by ITS-DNA PCR generated a specific fragment of 550 bp. The analysis of the ITS region of the sequences of these ten (10) isolates showed maximal correspondence with different strains of M. anisopliae and Metarhizium pinghaense.