STUDIES ON INTRODUCTION AND UTILIZATION OF THE PINE CATERPILLAR DENDROLIMUS SPECTABILIS CPV

The pine caterpillar Dendrolimus spectabilis CPV (JDS-CPV) introduced from Japan could give high mortality both to seven species of the pine caterpillar in the genus Dendrolimus and to the cotton borer Heliothis armigera in China.According to the study of gel profiles of CPV-RNA the JDS-CPV is different from the strains which replicated in the Dendrolimus spp.in China.So far we have found three types of gel profiles of nucleic acid.JDS-CPV belongs to type one.JADP-CPV,JYDPW-CPV,JGDP-CPV,CYDPW-CPV etc.belong to type two.The up band of CGDP-CPV belongs to type three.Type two and three are reported for the first time.JDS-CPV affects only the midgut epithelial cells as all other CPVs.The LC50 for the third-instar and fifth-instar larvae of the first generation are 1.6×105 CPB/ml and 3.3×105 CPB/ml respectively.The LD60 for the third-instar larvae of the same generation is 2.1×103 CPB/Iarva by bioassay.The JDS-CPV not only gave the best control to the larvae,but also affected feeding,body weight and even the survial rate of larvae of the next generation.Applying the mixture of JDS-CPV and Bt resulted in 72-80% reduction of feeding.After storaging it in oil emulsion at 4℃ for 197 days or in liquid suspension under 4℃ for five years,the biological activity of JDS-CPV could not be affected noticeably.The host used for mass production of JDS-CPV are the pine caterpillar larvae from pine plantation.An average yield obtained is more than 2×103 CPB per larva of 6-7th-instar.