Abstract
A multiply enveloped nuclear polyhedrosis virus fromMamestra brassicae has been shown to be morphologically similar to other baculoviruses. The virus particles contain 13 polypeptides of which 4 are associated with the nucleocapsid. The polyhedron comprises of one major polypeptide of molecular weight 28,000. The DNA has a mol. wt. of about 1.15×108, which is larger than that reported for other baculoviruses. The DNA is a circular, supercoiled molecule of CG mol. fraction 0.448. DNA fragments produced by a range of restriction enzymes are presented as an aid to identification.