Electron microscope observations of Autographa californica (Noctuidae) nuclear polyhedrosis virus replication in the midgut of the saltmarsh caterpillar, Estigmene acrea (Arctiidae)

The nuclear polyhedrosis virus from Autographa californica was studied with the electron microscope in the midgut of the salt marsh caterpillar, Estigmene acrea. The results of the present study were compared with a previous study in which the same inoculum was fed to Spodoptera exigua. In Estigmene acrea polyhedra were produced, but virions were not occluded. Nonoccluded virions were found throughout the midgut cytoplasm and budding into the hemocoel. Within the cytoplasm, the rough endoplasmic reticulum was observed to contain paracrystalline proteinaceous bodies. Fibrous bodies and annulate lamellae were also found in the cytoplasm of infected cells.