Se aisló al entomopatógeno Beauveria bassiana, desde poblaciones de Xanthogaleruca luteola, recolectadas en olmos de la provincia de Buenos Aires. In vitro se evaluaron 2 métodos de inoculación sobre desoves y larvas: mediante espolvoreo e inmersión en suspensión acuosa de los conidios del hongo. Ambos resultaron efectivos (principalmente el primero), para el biocontrol de la vaquita del olmo.From adults of Xanthogaleruca luteola collected in elm trees of the Buenos Aires province (Argentina) the entomopathogenic fungus Beauveria bassiana, was isolated. Two inoculation methods in spawns and larvae were evaluated in vitro: through powdering and submersion in aqueous suspension of the conidia. Both methods were effective (specially the former) for the biocontrol of "elm leaf beetle".Facultad de Ciencias Agrarias y Forestales