Abstract - Biological control using Beauveria bassiana has very low conidial virulence and persistence. This research aims to study the virulence and persistence factors of B. bassiana against Plutella xylostella, which was isolated from peatland in Central Kalimantan, Indonesia. There were four isolates of B. bassiana (B1M3T3S2, B1P1T1S1, B1M3T3S1, and B2P3T3S1), which were arranged in a Complete Randomized Design. Virulence was tested on P. xylostella larvae. Mortality of larvae was observed. Persistence was determined by the calculation of conidia numbers after UV irradiation. Conidia numbers were calculated after inoculation. The virulence test results showed that B1M3T3S2, the isolate with a conidia concentration of 108 conidia/mL, caused the highest mortality in P. xylostella larvae. The persistence test showed that B1M3T3S2 had the densest spore and highest growth rate. B1M3T3S2, an indigenous isolate, was the best isolate as a biological control agent of P. xylostella.