感染水椰八角铁甲的绿僵菌的分子鉴定及致病力测定
Molecular identification and pathogenicity assay on Metarhiziumagainst Octodonta nipae (Coleoptera: Chrysomelidae)
徐利1,蓝江林2,侯有明1**,陈玉森1,陈智雄1,翁章权1
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作者单位：1农业部亚热带农业生物灾害与治理重点开放实验室 福建农林大学植物保护学院福州350002；
中文关键词： 水椰八角铁甲, 金龟子绿僵菌小孢变种, ITS序列分析, 致病力测定
英文关键词：Octodonta nipae, Metarhizium anisopliae var. anisopliae, ITS sequence analysis, virulent bioassays
中文摘要： 在室内饲养的水椰八角铁甲Octodonta nipae（Maulik）种群中，发现有大量甲虫被病原菌感染致死。对死虫体表的病原真菌进行分离鉴定，并依据ITS序列分析鉴定，确定该病原真菌为金龟子绿僵菌小孢变种（Metarhizium anisopliae var. anisopliae）。经室内致病力测定，接种浓度分别为1.0×105～1.0×1010 cfu·mL-1孢子悬浮液，在接菌后10 d，成虫致病力方程为y =-4.992 + 5.623 x，LC50对数剂量为7.721；幼虫致病力方程为y =-4.335 + 5.368 x，LC50对数剂量为6.420。结果表明金龟子绿僵菌小孢变种对水椰八角铁甲幼虫和成虫具有高的致病力，且浓度越高感染率越高，相同浓度条件下幼虫的感染率较成虫高。金龟子绿僵菌小孢变种在水椰八角铁甲生物防治中具有较强的应用潜力。
英文摘要： High adult and larval mortality due to infection with a pathogenic fungus was observed when rearing Octodonta nipae (Maulik) under laboratory conditions. ITS sequence analysis identified the fungus as Metarhizium anisopliae var. anisopliae. The effect of inoculating 3rd instar larvae and adults of O. nipae with six different concentrations of M. anisopliae var. anisopliae was investigated.Doseresponse bioassays showed that M. anisopliae var. anisopliae had a high level of toxicity to both larvae and adults. At concentrations ranging from 1.0×105 cfu·mL-1to 1.0×1010 cfu·mL-1, the virulence equations on the 10th day after infection were y =-4.335 + 5.368 x and y =-4.992 + 5.623x for larvae and adults, respectively. The estimated logarithm of median lethal concentration was 6.420 and 7.721 for larvae and adults, respectively. These results indicate that M. anisopliae var. anisopliae was highly virulent against O. nipae larvae and adults and that the degree of virulence increased with increasing concentration. The infection rate was higher in larvae than in adults at the same concentration. These results indicate that M. anisopliae var. anisopliae could be a potential biological control agent for O. nipae.