COMBINED TOXICITY OF METARHIZIUM ANISOPLIAE WITH SUBLETHAL DOSES OF CHLORPYRIFOS, FIPRONIL AND CHLORANTRANILIPROLE AGAINST PERIPLANETA AMERICANA (DICTYOPTERA: BLATTIDAE)

The toxicity of commercial formulations of chlorpyrifos, fipronil, and chlorantraniliprole was tested alone and in combination with Metarhizium anisopliae against adult Periplaneta americana (Dictyoptera: Blattidae). The tested insecticides were applied topically and in case of their separate use, the mortality data was recorded after 12, 24 and 48 h of application. While mortalities for the combine application of insecticides and M. anisopliae were reocorded after 4, 7 and 14 d of application. In bioassay 1, chlorpyrifos was used at the dose rates of 100, 200 and 300 ppm, fipronil at 50, 100 and 150 ppm and use rates for chlorantraniliprole were 10, 20 and 30 ppm. Results exhibited that mean percent mortality of cockroaches in bioassay 1 was higher for the chlorantraniliprole (60%) followed by fipronil and chlorpyriphos after each exposure interval. Combined use of insecticides and fungus in bioassay 2 resulted in significantly higher mortality levels approaching 100% in all the combinations. In this case, highest mortality rates were observed for chlorantraniliprole + M. anisopliae followed by fipronil + M. anisopliae and chlorpyriphos + M. anisopliae. The higher mortality percentages of cockroaches in combined treatments as compared with alone highlights the ability of insecticides to be integrated with M. anisopliae.