A STUDY ON THE NUCLEAR POLYHEDROSIS VIRUS OF THE POPLAR LOOPER (APOCHEIMA CINERARIUS) Ⅳ. RECOVERY TESTS OF VIRUS

Several methods for recovery procedure of the polyhedral inclusion bodies of nuclear polyhedrosis virus of the poplar looper, Apocheima cinerarius, were compared. Recovery tests indicated that the PIB of AciNPV were precipitated from the concentrated suspensions in 7.4-8.4% solutions of lactose by adding acetone. Counts of the final preparation showed 4.96×1010 PIB/g. Yields of 80.5% were obtained. Bioassay tests indicated that the pathogenicity of the fresh preparations recovered was very good for the early third-instar larvae. The LC50 and 95% fiducial limits acre 2.84×103 PIB/ml and 1.70×103-4.96×103 PIB/ml respectively.In this procedure, costly centrifugal equipment was omitted, 1500-3000g diseased larvae could be reduced to final production in 3hr with laboratory general equipment. In this case, the virus formulation prepared may be used to control the poplar looper larvae in about 30-65 ha in the forest. Mass production has been proved to be a useful replacement for the centrifugation method, and the cost of the recovery virus is cheap.