Identification Of New Virus Strain Of Apocheima Cinerarius And The Assay Of Its Biological Activity

In order to develop new biological insecticides,we isolated a new virus strain from the larva of Apocheima cinerarius which died naturally.Observation by electron microscope,the new strain was preliminarily confirmed to be a cypovirus,and its lethal effect of the 3rd instar larvae of A.cinerarius and the 3rd instar larvae of Dendrolimus kikuchii was assessed by diet poison,and studied the synergistic effect between the new strain and NPV(Nuclear polyhedrosis virus).(1)The inclusion body of the new virus strain is polyhedron,and one polyhedron contains multiple virions.There was no significant difference in morphology from other CPV,and it was identified as a cytoplasmic polyhedrovirus.The new virus was named Apocheima cinerarius cypovirus(ApciCPV).(2)ApciCPV was virulent against the 3rd instar larvae of A.cinerarius,with LC50 of 1.42×104 OBs/mL.When the 3rd instar larvae of A.cinerarius were exposed to ApciNPV+ApciCPV mixture,compared with single dose of DekiNPV,LT50 was significantly shortened by 0.5?10.9 d,and the final mortality rate was increased by 6.7%-43.3%.A certain concentration of ApciCPV enhanced ApciNPV,and the potentiation was proportional to the concentration of ApciCPV in the mixture.(3)ApciCPV was virulent against the 3rd instar larvae of Dendrolimus kikuchii,with LC50 of 6.62×105 OBs/mL.When the 3rd instar larvae of D.kikuchii were exposed to DekiNPV+ApciCPV mixture,compared with single dose of DekiNPV,LT50 was significantly shortened by 0.5?20 d,and the final mortality rate was increased by 2.8%?66.2%.A certain concentration of ApciCPV enhanced DekiNPV,and the potentiation was proportional to the concentration of ApciCPV in the mixture.(4)There is synergistic effect between high concentration of ApciCPV and NPV,and it is proportional to the concentration of ApciCPV in the compounding agent.When the concentration of NPV in the compounding agent increases,the synergistic effect gradually weakens and finally presents as an additive effect.The low concentration of ApciCPV and NPV showed more additive effects and antagonistic effects.