Abstract

The banana weevil Cosmopolites sordidus (Germar) is the most important insect pest of banana and plantain (Musa spp.). The larvae by its trophic activities bore into the corm, present roots are destroyed and the emergence of new roots is delayed, reducing nutrient uptake and weakening the stability of the plant. Attacks in newly planted banana stands can lead to crop failure. In established fields, weevil damage can result in reduced bunch weights, mat die-out and shortened stand life. Damage and yields losses tend to increase with time. Banana weevil has been implicated as a primary factor contributing to the decline and disappearance of East African highland cooking banana from its traditional growing areas in central Uganda. Control measures are essentially based on the use of chemicals. Adult resistance, environnemental pollution, most toxicity to famers also to consumers, and its effect on non target insect were negative side effects of chemicals. Alternative sustainable methods (use of parasitoïds, predators, mass trapping with or without pheromon) were experimented, but results were few interest. Biological control using entomopathogenic fungi within genera Metarhizium and Beauveria bassiana were performed. Although promise results are shown in preliminary studies, efficient delivery systems still need to be developed. Research protocols for the development of a microbial control program of banana weevil using Metarhizium has focused in Côte d’Ivoire since 2008. It based on inoculated disk on stump traps (culombia trap), pheromon traps, pseudostem traps including its gregariousness to disseminate inoculum among weevils for sanitation of established field and biorationals. So these methods appear to be the promise ones significantly least fastidious and economic.

Keywords: C. sordidus; Entomopathogenic fungus; Mass trapping;Inoculated trap; Sordidin pheromone; Organic substrate