Encapsulation of Beauveria bassiana in Polysaccharide-Based Microparticles: A Promising Carrier System for Biological Control Applications

Beauveria bassiana is an entomopathogenic fungus that is widely used as a biocontrol agent against various insect pests in agriculture. However, its efficacy is limited by several factors such as ultraviolet radiation, high temperatures, and low humidity. These limitations can be overcome by microencapsulating B. bassiana, which protects the fungus and facilitates sustained release of the fungus. In the present study, we aimed to develop microencapsulated formulations of B. bassiana using a spray-drying technique and to evaluate their physicochemical properties, shelf life, and biological activity against two-spotted spider mites (Tetranychus urticae). Temperature and matrices influenced the physicochemical characteristics of B. bassiana formulations, with matrix mixing being the most promising strategy for more stable formulations. The formulations presented a mean size of 8–30 μm, indicating good potential for biocontrol applications. Biological assays demonstrated that the microencapsulated formulations increased the performance of B. bassiana against two-spotted spider mites, and even low conidial concentrations of B. bassiana in the formulations resulted in high mite mortality rates. These findings indicated that microencapsulation can improve the efficacy of B. bassiana as a biocontrol agent and overcome some of its limitations. Therefore, the development of microencapsulated formulations has promising prospects for use in integrated pest management programs, providing sustainable and environment-friendly alternatives to conventional pesticides.