Abstract
Cyto- and histopathological observations of the Plutella xylostella larva infected with the granulosis virus were carried out using electron microscope. Fat body cell of the larva infected with the virus showed hypertrophy of nucleus, protrusion and subsidence of nuclear membrane.
In advanced infection stages, disappearance of nuclear membrane was observed. However, appearance of the virus within the nuclear matrix was not confirmed. Formation of inclusion body of the virus occurred within the cytoplasm of brain and epidermal cells. Structure of the inclusion body was the exactly same as that formed in the cytoplasm of fat body cell. However, multiplication of the virus was not observed in mid gut tissue, cuticle layer of integument and silk gland. Aside from these studies, color changes of the pellet of purified inclusion bodies in wet circumstance were seen within the hue ranges of pale purplish pink, pinkish white, grayish white, greenish white and pale green under the sun light. However, those color changes disappeared after the desiccation or alkali treatment of the pellet.
