Previus test with several entomopathogenic fungus species on Monalonion dissimulatum Distant bug (Hem.; Miridae) gave priority to 1he pathogen Beauveria bassiana (Bals.) Vuill. Two B. bassiana strains were evaluated: one of them comming from Metamasius hemipterus sericeus (Olivier) (Col.; Curculionidae) (Bb T 011) and the other isolated from M. dissimulatum (Bb 012), to 1 x 106,2.5 X 103,5 X 108,7.5 X 103 and 1 x 109 conidium/ml increasing dosage. All insects treated independently of its biologycal state of development were susceptibles to 1he pathogenic attack of 1he two strains. For OO1hfungis strains 1he dosage at which a higher percentage of significant mortality was obtained ranged between 2.5 x 103 and 7.5 x 1011 conidium/ml with mortality was ranged between 33.75 -49.75 and 43.75 - 62.5 for Bb T 011, 68.75 - 86.87 and 78.12- 89.37 for Bb 012 in 10 and 15 days respectivetly.