Technology of a novel conidia-tablet formulation and packaging type to increase Beauveria bassiana (Hypocreales: Ophiocordycipitaceae) shelf life at room temperature

Abstract

Description of the subject. This study describes development of mycoinsecticide formulations containing dry conidia of the entomopathogenic fungus Beauveria bassiana combined with various inert excipients in tablet form to facilitate conidia dispersion in water and to maintain viability during storage. Objectives. This study aimed to evaluate the tablet formation of B. bassiana conidia associated with different inert excipient under direct compression in a hydraulic press. Method. Evaluation and validation of the mechanical and storage properties of conidial tablets in different types of packaging. Results. The tablet formulation containing 30% conidia (active ingredient) and 70% cornstarch (inert excipient) displayed satisfactory results regarding mechanical resistance and dispersion in water. This tablet exhibited hardness and friability of 173.94 N and 0.34%, respectively. The tablet disintegration rate in water occurred in 2 min, presenting a rapid dispersion of 109 conidia∙ml-1. Tablet stored in polyethylene pot with polymerized silica exhibited viability ≥ 80% over 180 days storage (25-28 °C). Conclusions. The formulation-packaging binomial is promising, considering the physical-chemical tablet parameters and the viability data. The conidia:cornstarch tablet type formulation provides a relevant cost-benefit ratio of a simple production process of a bioinsecticide, besides the use of low-cost adjuvant and packaging (polyethylene pot). Considering that most biopesticide products require storage under refrigeration, this work becomes important since the formulation remained viable for 180-days storage under room temperature conditions.