The fate of pea enation mosaic virus in its pea aphid vector, Acyrthosiphon pisum (Harris)

The fate of pea enation mosaic virus (PEMV) in its primary vector the pea aphid, Acyrthosiphon pisum (Harris), was studied by ultrathin sectioning and conventional transmission electron microscopy. PEMV virions were highly concentrated in the lumen of the midgut and hindgut, and also invaded a variety of tissues in the vector. Virions were detected in viroplasmlike areas, in defined structures in the cytoplasm, and in the nuclei of midgut epithelial cells. Virions also were seen in electron-dense areas in the cytoplasm of midgut muscle cells and hemocytes. Electron-dense structures containing viruslike particles occurred in the cytoplasm of the fat body. Organs and tissues in which PEMV could not be detected include the epidermis, mycetome, ovaries, tracheal system, foregut and hindgut epithelium and musculature, skeletal musculature, eye tissues, nervous system, and salivary system.