Population dynamics of sucking pests in green gram, Vigna radiata (L.) Wilczek

Among the four sucking pests; Aphid, Aphis craccivora Koch and jassid, Empoasca kerri exhibited their peak activity during the 19th SMW, with populations of 6.25 per and 3.20 per three leaves, respectively. The peak population of whitefly, Bemisia tabaci Gennadius (6.30/3 leaves), was observed during the 21st SMW. In the case of thrips, Megalurothrips usitatus, the population reached a peak level (4.20/3 flowers) during 21st SMW. Among various abiotic factors, wind velocity exhibited significant or highly significant positive correlation with sucking pests viz., aphid, jassid and whitefly incidence. Weather parameters viz., minimum temperature (r = 0.70), evening relative humidity (r = 0.79), and evaporation (r = 0.74), exerted a significant positive impact on thrips population in summer green gram. The ladybird beetle showed a highly significant positive correlation with A. craccivora (r = 0.92) and E. kerri (r = 0.92) populations. Green lacewing exhibited a highly significant and positive correlation with E. kerri (r = 0.91) incidence, whereas significant and positive correlation with A. craccivora (r = 0.751*) and B. tabaci (r = 0.790*) populations. The population of spiders showed a highly significant positive correlation with aphid (r = 0.98) and jassid (r = 0.94) populations in green gram crop.