The efficiency of singular and joint usage of third larval instars of ladybeetle, Hippodamia variegata (Goeze) and green lacewing, Chrysoperla carnea (Steph.) was studied against cotton aphid, Aphis gossypii Glover on cucumber plants in greenhouse. The predator-prey ratio of 1:30 reduced the population of pest significantly. Singular and joint usage of predators, however, was not significantly ...