Relative Toxicity of Certain Insecticides to Australian Ladybird Beetle, Cryptolaemus montrouzieri Mulsant

In order to determine the relative toxicity of certain insecticides to Cryptolaemus montrouzieri Mulsant, a laboratory study was carried out during 2009 to 2010. Ovicidal action of insecticides to eggs of C. montrouzieri revealed that maximum (80.92%) mortality of eggs was observed in indoxacarb followed by endosulfan, chlorantraniliprole and flubendiamide. Minimum (17.01%) mortality was registered in quinalphos followed by dichlorvos, triazophos and acephate. Significantly highest (75.71%) mortality of larvae was registered in quinalphos over rest of the other insecticides evaluated through topical application. Dichlorvos registered significantly least (7.87%) larval mortality. Dichlorvos and spinosad found to be safer insecticide when evaluated through dry film method. Quinalphos, endosulfan and acephate proved relatively more toxic to the larvae. Toxicity of insecticides applied topically to adults of C. montrouzieri indicated that quinalphos, endosulfan, acephate, chlorantraniliprole and indoxacarb found relatively more toxic and caused over 50% mortality. Dichlorvos and spinosad caused less (13.32 to 21.46%) mortality. Maximum (55.80%) mortality of beetles was found in quinalphos followed by endosulfan (52.69%) and chlorantraniliprole (46.98%). Dichlorvos and spinosad registered significantly low (9.90 to 14.14%) mortality over rest of the tested insecticides.