春尺蠖新病毒株的鉴定及其对春尺蠖核型多角体病毒的增效作用

春尺蠖在我国危害严重，为了挖掘具有开发潜力和应用前景的生防因子，本文分离纯化一株能够感染春尺蠖幼虫的新病毒，生物活性测定了新病毒株的毒力及其对春尺蠖核型多角体病毒（ApciNPV）的增效作用。新病毒株的超微结构观察表明，该病毒多角体多为切面呈六边形的多面体，直径大小为0.32～1.20 μm，病毒粒子呈近球状，具有质型多角体病毒的结构特征，命名为春尺蠖质型多角体病毒（ApciCPV）。生物活性测定结果显示，ApciCPV对春尺蠖3龄幼虫有很强的毒力，半致死浓度（LC₅₀）为1.42×10⁴ OBs/mL。当感染春尺蠖3龄幼虫时，ApciCPV可使ApciNPV半致死时间（LT₅₀）缩短0.50～10.90 d，使ApciNPV对春尺蠖的最终致死率提高6.70%～43.33%。根据最终致死率、LT₅₀以及ST三个值综合决定，当ApciNPV和ApciCPV配比浓度分别为1.0×10⁶和1.0×10⁴ OBs/mL时，对春尺蠖3龄幼虫的感染效率最高。新分离的ApciCPV病毒株是控制春尺蠖虫口密度的理想生物因子。

Identification of New Virus Strain of Apocheima cinerarius and Its Synergistic Effect on A. cinerarius Nucleopolyhedrovirus

Apocheima cinerarius (Erschoff) is one of the major insect pests in China. A new virus strain that can infect the larvae of A. cinerarius was isolated and purified, and measured for its virulence and synergistic effect to A. cinerarius nucleopolyhedrovirus (ApciNPV). The ultrastructural observation of the new strain showed that the virus was mostly of a hexagonal polyhedron, with a diameter of 0.32~1.20 μm, and with nearly spherical virion. With the structural features of a cypovirus, the virus was named as ApciCPV. Biological activity assays showed that ApciCPV was virulent against the 3^rd instar larvae of A. cinerarius, with LC₅₀ of 1.42×10⁴ OBs/mL. Interestingly, ApciCPV showed a synergistic effect to ApciNPV. When the 3^rd instar larvae of A. cinerarius were exposed to ApciCPV in combination with ApciNPV, LT₅₀ of ApciNPV to the larvae was significantly shorten by 0.50-10.90 d, and the final lethal rate of ApciNPV increased by 6.70%-43.30%. Based on mortality, LT₅₀ and ST, the mixed solution of 1.0×10⁶ OBs/mL ApciNPV and 1.0×10⁴ OBs/mL ApciCPV, has the most virulence against the 3^rd instar larvae of A. cinerarius. These results show that the newly discovered viral strain, ApciCPV, is one of the ideal biological agents to control A. cinerarius.