The blood-sucking bugTriatoma infestansis the main Chagas disease vector in the Southern Cone of Latin America. Populations resistant to pyrethroid insecticides have been detected in the early 2000s and then expanded to the endemic area of northern Salta province, Argentina. In this context, the entomopathogenic fungusBeauveria bassianahas been shown to be pathogenic to pyrethroid-resistantT. infestans. In this study, both the bioinsecticidal activity and the residual effect of an alginate-based microencapsulation of a native strain ofB. bassiana(Bb-C001) were tested under semi-field conditions against pyrethroid-resistantT. infestansnymphs. Fungal microencapsulated formulation caused higher nymph mortality than the unmicroencapsulated fungus and contributed to maintaining the conidial viability throughout the period evaluated under the tested conditions. These results suggest that alginate microencapsulation is an effective, simple, low-cost method that could be incorporated into the formulation of a bioinsecticide as a strategy to reduce the vector transmission of Chagas disease.