Biology and predatory potential of green lacewing (Chrysoperla carnea) (Neuroptera : Chrysopidae) on different insect hosts

Laboratory experiments were conducted during 1997 to study the biology and predatory potential of the green lacewing, Chrysoperla carnea (Stephens) on eggs of Corcyra cephalonica Stainton, Earias vitella Fabricius and Helicov erpa armigera Hubner, neonate larvae off. vitella and H. armigera, Aphis go ssypii Glover collected from cotton (Gossypium hirsutum L.), okra (Hibiscus esculentus L.) and guava (Psidium guajava L.) and Aphis craccivora Coch. c ollected from cowpea [Vigna unguiculata (L.) Walp.] and groundnut (Arachis hypogaea L.). The egg, grub and pupal period. of C. carnea were minimum on A. craccivora collected from groundnut and maximum on H. armigera neonate l arvae recording 2.35, 8.22 and 8.02, and 3.10, 11.37 and 8.27 days, respect ively. The total developmental period of C. carnea on different insect host s ranged from 18.59 [A. craccivora (groundnut)] to 22.74 days (H. armigera neonate larvae). C. carnea adult laid a maximum of 318.40 eggs when reared on A. craccivora collected from cowpea followed by A. gossypii (okra), A. g ossypii (guava) and A. gossypii (cotton), recording 271.20, 266.80 and 262. 40 eggs/female respectively. Hatchability of eggs of C. carnea was more tha n 80% when reared on A. craccivora (cowpea) and eggs of of C. cephalonica a nd E. vitella. Predatory behaviour of C. carnea was evident from its prefer ence for eggs of insect hosts. The aphid A. craccivora from groundnut can b e utilized for restoring the fecundity and predatory activity of C. carnea in laboratory if found lossing due to; continuous use of C. cephalonica.