Thanh Duong Danh, Nishi Oumi, Wasano Naoya, Yasunaga-Aoki Chisa
The Western Highland Agriculture and Forestry Science Institute, 53 Nguyen Luong Bang Street, Hoa Thang Conmune, Buon Ma Thuot, Dak Lak province, 632-183, Viet Nam; Laboratory of Insect Pathology and Microbial Control, Institute of Biological Control, Faculty of Agriculture, Graduate School, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, 819-0395, Japan.
Laboratory of Insect Pathology and Microbial Control, Institute of Biological Control, Faculty of Agriculture, Graduate School, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, 819-0395, Japan.
Fungal Biol. 2025 Aug;129(5):101612. doi: 10.1016/j.funbio.2025.101612. Epub 2025 Jun 2.
The common cutworm (Spodoptera litura, Lepidoptera: Noctuidae) is one of the most widespread pest insects affecting various crops in Asian countries. To screen promising biological control agents for this pest, we isolated 49 potential entomopathogenic fungal isolates from 25 soil samples using S. litura and four additional insect species as baits. The results revealed a high occurrence (24 %) of Cordyceps cicadae in soil through the bait method with all five insect baits, following the Metarhizium anisopliae complex (52 %), despite Cordyceps cicadae generally being known as a specialist entomopathogenic fungus of cicada nymphs. Molecular phylogenetic analysis demonstrated that Cordyceps cicadae isolates from soil and natural cicada nymphs clustered together at a terminal node with previously reported Cordyceps cicadae from cicada nymphs and C. lepidopterorum from lepidopteran larvae. Virulence assays against last-instar larvae of S. litura revealed significant variability in virulence among C. cicadae strains derived from soil and cicada nymphs. Among these, C. cicadae S17, isolated from soil using S. litura as bait, exhibited virulence comparable to the most virulent strains of the M. anisopliae complex and was also virulent against third-instar larvae and pupae. Our findings indicate that C. cicadae exhibit a broader host range than previously recognized, with potential applications in biological control for larvae and pupae of S. litura.
斜纹夜蛾（Spodoptera litura，鳞翅目：夜蛾科）是亚洲国家影响多种作物的分布最广的害虫之一。为了筛选针对这种害虫有前景的生物防治剂，我们以斜纹夜蛾和另外四种昆虫为诱饵，从25个土壤样本中分离出49株潜在的昆虫病原真菌菌株。结果显示，尽管蝉拟青霉通常被认为是蝉若虫的专性昆虫病原真菌，但通过用所有五种昆虫诱饵的诱饵法，在土壤中蝉拟青霉的出现率很高（24%），仅次于绿僵菌复合体（52%）。分子系统发育分析表明，从土壤和天然蝉若虫中分离出的蝉拟青霉菌株在一个末端节点处聚集在一起，与先前报道的来自蝉若虫的蝉拟青霉和来自鳞翅目幼虫的鳞翅拟青霉聚在一起。对斜纹夜蛾末龄幼虫的毒力测定表明，来自土壤和蝉若虫的蝉拟青霉菌株之间的毒力存在显著差异。其中，以斜纹夜蛾为诱饵从土壤中分离出的蝉拟青霉S17表现出与绿僵菌复合体中最具毒力的菌株相当的毒力，并且对三龄幼虫和蛹也有毒力。我们的研究结果表明，蝉拟青霉的宿主范围比以前认识到的更广，在斜纹夜蛾幼虫和蛹的生物防治中具有潜在应用价值。
