The aerial conidia of the entomopathogenic fungus Beauveria bassiana served as the basis for the preparationof
the wettable powder and inverted emulsion formulations. We evaluated the insecticidal efficacy of preparedconidia against the second-instar larva of the Cotton leafworm, Spodoptera littoralis, according to storagetemperature in order to establish the ideal conditions for long-term storage. The formulations' pathogenicity to S. littoralis larvae varied significantly, according to an analysis of mortalitydata. The formulation that best preserved the pathogenicity of conidia for a longer period of time was wettablepowder. Formula kept at freezing conditions -10°C was more virulent comparing to formula kept at coolingconditions 4°C and at the room temperature (25°C). This finding implies that conidial pathogenicityismaintained at low and moderate temperatures.