An ultrastructural study of the development of a nuclear polyhedrosis virus of the eastern hemlock looper, Lambdina fiscellaria fiscellaria

Abstract

The development of a nuclear polyhedrosis virus of the eastern hemlock looper, Lambdina fiscellaria fiscellaria, is described in gut and hypodermal tissues. Infection was found in the midgut cells where a cycle of virus replication occurred but no polyhedron formation was observed. In the hypodermis the mode of viral development was similar to that recorded for other nuclear polyhedroses which have bundles of virions surrounded by membranes and occluded in polyhedra. At an advanced stage of infection, non-occluded virions formed regular arrays in some of the infected nuclei. Other non-occluded virions were found in the cytoplasm and in large numbers near the periphery of cells. Angular cytoplasmic inclusion bodies showing the structure of polyhedron protein, but containing no virions, were associated with virus-infected cells in both the tissues examined.