Biochemical , Histological Studies of Pectinophora gossypiella (Saund.) Viral Infected Larvae Supported by Scanning Electron Microscope Inspections

Abstract

A lot of pink bollworm (PBW) Pectinophora gossypiella full grown larvae were excluded from cotton bolls collected from Sakha, Kafr El-Shiekh Governorate, Egypt. Larvae were transferred to laboratory of Bollworms Department, Plant Protection Research Institute, ARC, Dokki, Giza. The healthy appearance PBW larvae were placed individually in sterilized glass tubes (2x7cm) plugged with cotton wool under room conditions and observed 2 times/ week. Infected larvae with baculuviruses (NPV & GV) were collected. Present study clarified and discussed the pathogenicity of baculuviruses against PBW resting larvae in many views (appearance, histology and biochemistry). Results indicated that, the activation of PBW chitinase (CHT) at the resting period enhances the insecticidal activity of latent baculuviruses. So that the baculuviruses overcome apoptosis and prevent ecdysis of PBW resting larvae. And the scanning electron microscope and histology micrographs revealed the appearances of this infection as external scleroticzation, shrinking, swelling and internal degradation of P. gossypiella organs Furthermore, the biochemical analysis revealed decrease activity of larval chitinase with increase activity of both N-acetylglucosamine (NAG) and phenoloxidase. However, the utilizing of these epizootic baculuviruses as microbial control agents still need more studies of insect immune, insecticidal evaluation, molecular biology and environmental safety.