Abstract: Since DsCPV-1 (Dendrolimus spectabilis cytovirus 1) was discovered and separated from Dendrolimus spectabilis in 1965 in Japan, there have been 6 isolates of cytoplasmic polyhedrosis virus separated respectively from D. punctatus, D. tabulaeformis, D. spectabilis, D. p. tehchangensis, D. p. wenshangensis and D. superans in China. Electrophoretic analysis of the genome dsRNA of these CPV isolates showed that they all should be classified into the cytovirus 1 as the DsCPV-1. These Dendrolimus spp. CPV isolates can infect 35 species of insects in 10 families of Lepidoptera and have a well infectious ability and cause high mortality on many of them, so they also could be used in the control and these insects could be used as candidates for alternate hosts to produce Dendrolimus spp. CPV pesticides. The genome profiles of the viruses obtained from some insects infected by these Dendrolimus spp. CPV isolates are different from that of the inoculants, but related closely, if not identical, to viruses from these insects. These may be explained as that the occult viruses of hosts were activated by other viruses.

Key words: Dendrolimus spp., cytoplasmic polyhedrosis virus, host range, cross infection, occult viruses