An Icosahedral RNA Virus of the Soybean Looper (Pseudoplusia includens)

An icosahedral RNA virus isolated from Pseudoplusia includens is described. Purified virus preparations contained particles 40 nm in diam. with a sedimentation coefficient of 190S and a density of 1.33 g/ml. The virus consisted of 13 to 14% nucleic acid with a base ratio of A:25.8%, U:20.9%, G:30.8%, C:22.5%. Polyacrylamide gel electrophoresis demonstrated that the mol. wt. of the single-stranded RNA is 1.9 x 10⁶ and the mol. wt. of the major polypeptide is 55 000. The virus is not serologically related to the Trichoplusia ni and Antheraea eucalypti RNA viruses.