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

Abstract

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 Helicoverpa armigera Hubner, neonate larvae of E. vitella and H. armigera, Aphis gossypii Glover collected from cotton (Gossypium hirsutum L.), okra (Hibiscus esculentus L.) and guava (Psidium guajava L.) and Aphis craccivora Coch. collected 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 larvae recording 2.35, 8.22 and 8.02, and 3.10, 11.37 and 8.27 days, respectively. The total developmental period of C. carnea on different insect hosts 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. gossypii (guava) and A. gossypii (cotton), recording 271.20, 266.80 and 262.40 eggs/female respectively. Hatchability of eggs of C. carnea was more than 80% when reared on A. craccivora (cowpea) and eggs of of C. cephalonica and E. vitella. Predatory behaviour of C. carnea was evident from its preference for eggs of insect hosts. The aphid A. craccivora from groundnut can be utilized for restoring the fecundity and predatory activity of C. carnea in laboratory if found lossing due to continuous use of C. cephalonica.