From Scale-Up Production to Field Bioefficacy: Blastospore-Based Mycoinsecticides against Spodoptera frugiperda and

Abstract

Entomopathogenic fungi of the order Hypocreales produce hydrophilic, yeast-like cells named blastospores by submerged liquid fermentation, offering promising biological alternatives for managing insect pests. However, the widespread adoption of fungal blastospores has been constrained by their limited shelf life and often inconsistent field performance. To address these technological barriers, we developed and optimized a complete bioprocess for the production, scale-up, formulation, storage, and biological evaluation of blastospores from Beauveria bassiana BRM 14527 and Cordyceps javanica BRM 14526 for controlling Bemisia tabaci and Spodoptera frugiperda, two major agricultural pests. Nutritional conditions were optimized to enhance blastospore yields, with carbon-to-nitrogen ratios of 29:1 and 36:1 yielding up to 2.33 × 109 and 2.13 × 109 blastospores mL–1, respectively. Production in laboratory shake flasks and scale-up to 7-L and 1200-L bioreactors consistently yielded >1 × 109 blastospores mL–1 within 48 h. Oil–silica formulations significantly improved the shelf life of freshly produced blastospores (up to 3.49 × 108 CFU g–1 after 90 days at 4 °C) compared with unformulated preparations. In bioassays, oil-formulated blastospores retained high virulence against S. frugiperda larvae and B. tabaci nymphs, achieving 70–93% mortality when applied at 1 × 107 blastospores mL–1. In two consecutive soybean cropping seasons, 2022/23 and 2023/24, repeated applications of blastospores in oil dispersion effectively reduced infestations of B. tabaci nymphs. These findings support the industrial mass production of highly infective blastospores along with their oil dispersion formulations as fast-acting, short-term, storage-stable mycoinsecticides for integrated pest management.