Development of capsule formulation of Beauveria bassiana (Balsamo) Vuillemin

Capsule is a stable formulation wherein the bioagent is encapsulated in coatings and thus protected from extreme environmental conditions. In this study, various coating materials were tested for their stability based on the time taken for disintegration when kept under ambient conditions both in vitro and in vivo. The in vivo performance was assessed for placement in soil as well as in banana pseudostem. The coating materials tested was Hard Gelatin Transparent (HGT), Hard Gelatin Coloured (HGC) and Hydroxy Propyl Methyl Cellulose (HPMC), while the carrier materials used were talc, chitin, chitosan, sodium alginate and calcium alginate. The entomopathogen encapsulated was Beauveria bassiana (Balsamo) Vuillemin and the efficacy of product was assessed against pseudostem weevil, Odoiporus longicollis (Olivier). HGT was the best coating material as it was stable under room temperature and normal atmospheric humidity. For soil placement, chitosan based capsules in transparent gelatin coating took only 24 to 48 hr to disintegrate completely under varying soil moisture. Talc based capsules in transparent gelatin coating got disintegrated completely at the end of 24 hr when placed in banana pseudostem, owing to the receipt of sufficient humidity. Placement of capsules in leaf axils or pseudostem sheath can be adopted for prophylactic control of pseudostem weevil and placement in bore holes can be considered for curative application. The ideal moisture content of filler material for fungal encapsulation was determined as 10%. Through this research paper, we would like to disclose about the ideal coating material, carrier material and moisture content for the encapsulation of entomopathogenic fungi.