A biochemical and biological comparison of three European isolates of nuclear polyhedrosis viruses from Agrotis segetum

Isolates of multiply-enveloped nuclear polyhedrosis viruses from Agrotis segetum (Lepidoptera: Noctuidae) populations in England (AsNPVE), France (AsNPVF) and Poland (AsNPVP), were compared biochemically and for their infectivity to A. segetum and Mamestra brassicae larvae. The electrophoretic profiles of DNA restriction endonuclease fragments and viral proteins appeared identical for AsNPVE and AsNPVF. AsNPVP was distinct by these techniques, although some of the virus particle polypeptides had the same mobilities as those of the other isolates. A serological comparison of the A. segetum NPV isolates with other baculoviruses, using indirect enzyme-linked immunosorbent assay, suggested that AsNPVP was no more closely related than M. brassicae NPV to the other A. segetum NPV isolates. AsNPVP had significantly lower infectivity for neonate A. segetum larvae (LD50 = 350 inclusion bodies) than AsNPVE (10 inclusion bodies) or AsNPVF (23 inclusion bodies). AsNPVE and AsNPVF did not appear to replicate in M. brassicae larvae, while AsNPVP produced a limited infection in this species.