Field evaluation of selected formulations of Beauveria bassiana for the management of the banana weevil (Cosmopolites sordidus) on plantain (Musa spp., AAB group)

Field experiments were undertaken to determine the efficacy of two formulations of Beauveria bassiana isolate IMI331094 against the banana weevil, Cosmopolites sordidus. Oil palm kernel cake-based formulation of conidia (OPKC-C) and conidial powder (CP) were applied to the planting holes and suckers. After artificial weevil release, OPKC-C and CP gave the same high level of weevil mortality (75%) compared with only 1% in the untreated control. Under natural levels of weevil infestation, 42% of weevils collected from suckers treated with OPKC-C died compared with 6% and 3% weevil mortality for CP and the untreated control, respectively. None of the suckers treated with OPKC-C died during the study period (60 days) while 17% and 19% of suckers from the CP treatment and the untreated control respectively, were killed. A study on the spread of fungal conidia using artificially infected and non-infected adult weevils showed a possible dissemination of B. bassiana conidia from infected weevils up to 18 m from the release point. On the basis of these results, the isolate IMI330194 of B. bassiana could clearly play a key role in the management of C. sordidus adults on plantain.