Capsule formulations of Metarhizium anisopliae (Metchnikoff) Sorokin for the management of banana rhizome weevil, Cosmopolites sordidus (Germar)

The experiment was laid out as a pot culture study using five month old plants of banana variety Nendran. Plants were artificially infested with second instar grubs of Cosmopolites sordidus (Germar) and capsule formulation of Metarhizium anisopliae (Metchnikoff) Sorokin were placed in the rhizosphere @ four per plant. The efficacy was determined by determining the damage Index (DI), number of tunnels caused by the pest and the number of weevils present by destructive sampling. When applied prophylactically, chitosan based capsules were found to be superior to talc based capsules with DI values 36.67 and 46.67, respectively. Reduction in pest population observed was on par in plants treated with talc based and chitosan based capsules (55.56 and 47.22%). In curative treatment, both the capsules were equally effective with DI 26.67 and 30. There was 50% reduction in pests when treated with chitosan based capsules, while it was 58.3% in talc based capsules, the effect being similar. The experiment revealed that Metarhizium capsules based on talc or chitosan when applied as prophylactic and curative methods can effectively manage the banana weevil.