Comparative Toxicity of Quinalphos and Oxydemeton-O-Methyl on Life Stages of Dysdercus Koenigii (Fabr.)

Three concentrations of quinalphos and oxydemeton-o-methyl i.e. 0.001, 0.002 and 0.004% were topically applied on the thorasic terga of freshly emerged 4^th nymphal instar of Dysdercus koenigii with the help of micro applicator and the observations were made on mortality, nymphal longevity, fecundity, fertility and adult longevity of survived individuals. The total nymphal loss up-to adult emergence was 21.6, 31.6 and 54.9% in case of quinalphos, whereas, oxydemeton-o-methyl caused 21.6, 34.9 and 54.9% nymphal mortality, respectively. The longevity of the nymphs which survived by the treatment of both insecticides, was increased significantly, whereas, fecundity and fertility of the adults emerged from the survived treated nymphs, decreased significantly. On the basis of the present finding, it can be concluded that quinalphos is more toxic than oxydemeton-o-methyl.