Abstract: Purified suspension of nuclear polyhedrosis virus of Mamestra brassicae was inoculated in the abdominal cavity of guinea pigs at a dosage of 4×106 PIB per gram body weight.6 and 16 days after inoculation,pancreas was taken out for electron microscope examination.Strains of the polyhedrosis virus were found in the cells of pancreas sixteen days after inoculation.The suspensions of the liver,spleen and pancreas of the inoculated guinea pigs were prepared to rear the larvae of cotton ballworms(Heliothis armigera H.),and the infected larvae showed typical symptoms of the virus disease.The mortality of the infected larvae was either 70.83% for the anatomi cal treatment six days after inoculation,or 91.3% for the anatomical treatment sixteen days after inoculation.Typical polyhedras were also found in the dead bodies of the larvae by electron microscope examination.Therefore,it can be ascertianed that nuclear polyhedrosis virus of Mamestra brassicae can survive in the cells of guinea pig organs for sixteen days.Virus duplication in the guinea pig cells is also discussed in this paper.However,further research work should be done on the duplication of this virus in the cells of mammals.

Key words: Nuclear polyhedrosis virus of Mamestra brassicae L., Guinea pig, Ab-domnal cavity inoculation