Essais sur l'utilisation d'un biopesticide à base des conidies de Metarhizium flavoviride pour le contrôle des sauteriaux au Mali

Abstract

Abstract: Investigation on the use of a biological insecticide based on Metarhizium flavoviride for the control of grasshoppers in Mali. Metarhizium flavoviride Gams & Rozsypal (Deuteromycotinae; Hyphomycetes) was produced in diphasic culture, firstly in a sucrose‐yeast medium, with sporulation on rice. Spores were extracted in kerosene or sieved and dried. For application, the spores were formulated with a mixture of peanut oil and kerosene. The spore formulation was applied with spinning disk sprayers at Ultra‐Low Volume. From 1992 to 1994 several species of grasshoppers were treated with this formulation containing M. flavoviride conidia. Field applications resulted in mortality rates of 92% for Oedaleus senegalensis (Orth., Acrididae) (Krauss) treated with the Niger strain (IMI 330189) kept in field cages in 1992. In 1993, experiments compared two strains of M. flavoviride, the Niger strain (IMI 330189) and one from Mali (192–794). Mortality rates obtained for samples incubated in cages were between 31 % and 93%, respectively, for IMI 330189 (Day 0) and 192–794 (Day 3) for Krausella amabile (Orth., Acrididae) (Krauss). Field applications in 1994 resulted in cage mortality rates between 50% and 99% for O. senegalensis and K. amabile, respectively when treated with IMI 330189 and 192–794, with between 26% and 83% of dead insects showing external sporulation. Field counts in the 1994 experiment showed a population reduction of 85%.