This thesis aims to understand the role of Cosmopolites sordidus, the banana weevil which is the main pest of banana, in the epidemiology of banana wilt caused by the fungal pathogen Fusarium oxysporum f. sp. Cubense (Foc), a major disease of banana. The originality of this work lies in the fact that it explores the relationships between a pest, a pathogenic fungus and a plant. This thesis combines experimental approaches in controlled environment and in the field, which allowed to better disentangle the fungus-insect interactions and to determine the relative importance of these interactions in the epidemiology of this fusarium wilt. The steps of this work included i) the study of the differential attractiveness of healthy and diseased plants, ii) the ability of C. sordidus to acquire and transport Foc propagules, both internally and externally, ii) the ability of C. sordidus to infect healthy plants. In the experiments carried out in controlled environments, the presence of propagules transported by C. sordidus and their pathogenicity were verified by molecular approach and by pathogenicity tests. The results obtained showed that C. sordidus has the capacity to transport infectious propagules both externally and internally. Surprisingly, the results also showed a preferential attraction of C. sordidus to diseased plants compared to healthy ones. These results allow rethinking crop protection in an integrated way, with practical perspectives in terms of strategies to be implemented in the early phases of a Foc epidemic and more globally in a multi-pest approach. This includes the use of weevil control measures in the initial phases of Foc contamination. In a general way, this work also provides elements of discussion on the possible co-evolution of the insect-disease-plant complex.