Laboratory Evaluation of the Toxicity of Mineral Oil, Diazinon, Malathion and Chlorpyrifos on Ladybird, Cryptolaemus Montrouzieri Mulsant (Col.: Coccinellidae)

Acute toxicity of the field recommended concentration of three conventional insecticides (diazinon, malathion and chlorpyrifos) and mineral oil was evaluated on 3^rd and 4^th instar larvae and adults of cryptolaemus montrouzieri mulsant. the mortalities caused by the insecticides and mineral oil were significantly different. diazinon and malathion with 100% mortality showed the highest toxicity to the different stages of the ladybird. chlorpyrifos and mineral oil caused less than 30% mortality, while mineral oil had the lowest harmful effect on this predator. based on lc_50 and lc-90 values 24h after treatment, the male and female adults of c. montrouzieri were more susceptible to diazinon (701 and 635; 1257 and 1194ppm) than to chlorpyrifos (4238 and 4316, 5683 and 5480 ppm). based on international organization of biological control (iobc) classification, chlorpyrifos and mineral oil were classified as category 1 (harmless) and diazinon and malathion were placed in category 4 (harmful).