Evaluation of Certain Botanicals as Stressors of Nuclear Polyhedrosis Virus in Larvae of Helicoverpa armigera

Abstract

The gram caterpillar Helicoverpa (= Heliothis armigera ) is attacked by a nuclear polyhedrosis virus (NPV) (Rabindra and Subramanian, 1974). NPV is transmitted to the offsprings of host insects by vertical transmission (Hamm and Young, 1974) and often the virus can exist in the host population in occult form (Podgwaite and Mazzone, 1986). Such latent infections or occult viruses are some times activated by stress, both biotic and abiotic, resulting in the outbreak of the disease in the host insect populations (Aruga, 1963).