Four strains of Beauveria sp. (ABvPr11, ABvPr8, ABvPr3, ABvSr4), that were found in the locust Schistocerca piceifrons peruviana from Huamanga, Ayacucho, Peru, were isolated and morpho-logically characterized. Entomicidal activities of four strains were evaluated on the locust. Results showed that all the strains producing 100% mortality when using solutions of 108 conidias/mL. The time for 100% mortalities of the strains ABvPr11, ABvPr8, ABvSr4 y ABvPr3 were 12, 14, 14 y 16 days respectively. In the tenth day significant differences were observed between the mortality of the strains ABvPr11 (90%) and ABvSr4 (74%), ABvPr8 (72%), ABvPr3 (64,6%). Lethality time was determinate for the 50% (TL50) of the locust population: ranging from 8,38 to 9,16 days. Lethality time for the 80% (TL80) ranged from 9,6 to 11,5 days. The ABvPr11 strain presented the highest biocidal activity for the Schistocerca piceifrons peruviana L.A.