Chrysoperla carnea, Aphis gossypii, Aphis craccivora, Helicoverpa armigera, Earias vitella. neonate larvae, predatory potential

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 (Gassypium  hirsulum 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.