Electron and light microscope studies of the development of the virus rods of insect polyhedroses

Abstract

In 1915 Glaser demonstrated for the first time that a nuclear polyhedrosis of a lepidopterous larva (Lymantria dispar), was induced by an invisible filterable virus isolated from the blood of diseased larvae. Nuclear polyhedroses of the larvae of over a 100 insect species are now known, and those of them which have been investigated have been shown to be due to viruses. In these polyhedroses the nuclei of susceptible cells, hypodermis, tracheae, fat and blood cells, etc., enlarge and become packed with infectious crystalline inclusion bodies, the polyhedra, from which the diseases get their name. The pupae and imagos of these insects are not generally susceptible to polyhedral virus diseases, and so far no nuclear polyhedrosis of imaginal tissues in the larvae has been reported. This has led to the suggestion that imaginal tissues are not susceptible to polyhedral virus diseases.