EFFICACY OF SOME NATURAL HOSTS ON THE DEVELOPMENT OF CHRYSOPERLA CARNEA (STEPHENS) (NEUROPTERA: CHRYSOPIDAE) - A LABORATORY INVESTIGATION

Abstract

Biology and feeding potential of the predator, Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) were studied on different hosts with particular reference to cotton crop. Various hosts viz., aphids (nymphs/ adults) and the eggs of cotton bollworms were used for the rearing of C. carnea and compared with the factitious host, Angoumois grain moth (Sitotroga cerealella) eggs on which the culture of the predator is maintained for the last many generations at the laboratory. The studies indicated that larval and pupal durations of the predator were significantly affected by the change of the hosts and the total developmental period was significantly shorter when the predator was offered with aphids for feeding. The fecundity, fertility, pupation, hatchability and longevity of the predator were also higher on aphids followed by pink bollworm, spotted bollworm, Angoumois grain moth and American bollworm eggs. However, the sex ratio was not affected due to change in the type of hosts. An identical trend in all the observed parameters was recorded in parental and first filial generations on all the tested hosts. Based on the studies, aphids appeared to be the most promising host for mass rearing of the predator. Further, successful predation on the cotton bollworm eggs manifested the potential of C. carnea for the management of cotton bollworms in the field.