Species richness, diversity and evenness of predators of different species of aphids infesting various field crops

The population of natural enemies (predators) on Aphis gossypii were more in number compared to other crops with dominance of Cheilomenes sexmaculata (44.56%). For cowpea the highest relative abundance noted was of Coccinella transversalis (47.49%). C. sexmaculata was found dominat on Aphis gossypii, Uroleucon compositae, Rhopalosiphum maidis and Sitobion miscanthi with the percentage of 44.56, 49.26, 63.04 and 76.19, respectively. Scymnus spp. was most dominant (51.06%) predators of A. punicae on pomegranate. Brevicoryne brassicae on cabbage had abundance of Syrphid fly I. scutellaris 63.21%. The highest number of species of predators was on A. gossypii on cotton (10). A. gossypii also showed highest number for Margalef Index (R₁) and Menhinick Index (R₂) i.e. 1.13 and 0.74. Simpson's index of predators of A. gossypii showed lowest index (0.24) while the highest was seen in S. miscanthi (0.59). Shannon-Weiner index was lowest in predators of S. miscanthi (0.79) while the highest was observed in predators of A. gossypii (1.79). A. craccivora showed maximum value for Pielou's index and simpson's evenness index which was 0.85 and 0.73, respectively.