Abstract: In order to determine the insecticidal efficacy of Beauveria bassiana (Balsamo)Vuillemin (Hyphomycetes: Moniliales) and diatomaceous earth (Diafil 610) against Rhyzoperthadominica (F.) (Coleoptera: Bostrychidae) a laboratory assay was designed. The fungusB. bassiana was applied at 4.23 x 107, 4.23 x 108 and 4.23 x 109 conidia kg-1 of wheat individually aswell as mixed with 400 and 800ppm of Diafil 610. The conditions for the trials were 30±2°Cwith 55% RH and the counts for mortality were made after 8, 16 and 24 d. All the dead adultswere removed after every count and the vials were kept for next 60 d to assess the emergence ofF1 generation. The findings from these studies proved that the extended exposure interval and thehighest combined dose rate of the entomopathogenic fungus and the diatomaceous earth gave themaximum mortality of the beetles. The emergence of the progeny was also highly suppressedwhere the maximum dose rate of the synergized treatments were applied.