Abstract: We have propagated Pseudaletis unipuncta granulosis virus (synergistic strain) in larvae of Pseudaletis separata and have conducted quantitative evaluation of the enhancement of the P. unipuncta granulosis virus-Ps (PuGV-Ps) on the NPVs of P. separata (Ps), Heliothis armigera (Ha) and Agrotis segetum (As). The results show the PuGV-Ps enhanced PsNPV, HaNPV and AsNPV infections in their original host insects. The high proportions (55%-85%, 30%-80%) of enhancement were observed in the PsNPV and HaNPV assays, and the median one (15%-35%) was obtained in the AsNPV-PsGV system. A synergistic factor (PuSF-Ps) has been isolated from the PuGV-Ps system using gel filtration technique. When PsNPV polyhedra were mixed with 250 ng PuSF-Ps, the value of enhancement increased by about 80%. The molecular weight of the synergistic factor was determined with Sephadex 150 column (1.6cm× 90cm) to be about 160k.

Key words: Pseudaletis separata, PuGV-Ps, PuSF-Ps