Aphids are one of the most serious agricultural insect pests causing major economic losses to crops, both directly through cell destruction from their feeding and indirectly by transmitting plant diseases such as viruses. The knowledge of seasonal history of pest is very important because the biology of pest population is a result of interaction among individuals of the species and their habitats. In this book we have presented research data on natural enemies of aphids and toxicity of insecticides against aphids. The data on biodiversity indices, their formulae and methods also given. for easy understanding data is presented in graphical form with specific photographs. Whole data is given in tabular form along with seasonal occurrence, number of natural enemies observed and LC50 value of insecticides against particular species.