Departamento de Proteção Vegetal, Faculdade de Ciências Agronômicas, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, São Paulo, 18610-307, Brazil.
Departamento de Medicina Interna, Faculdade de Medicina de Botucatu, Universidade Estadual Paulista "Júlio de Mesquita Filho", Botucatu, São Paulo, 18618-970, Brazil.
Sci Rep. 2021 Mar 31;11(1):7233. doi: 10.1038/s41598-021-86638-9.
The eucalyptus snout beetle (ESB), Gonipterus platensis, is endemic to Australia but has become a major invasive, destructive pest of Brazilian eucalyptus plantations. Efforts to develop insecticides based on entomopathogenic fungi against ESB are limited by the lack of known virulent strains. We therefore explored the virulence of indigenous Brazilian strains of major entomopathogenic fungi-Beauveria spp. and Metarhizium anisopliae-against ESB adults. We found widely varying virulence and later capacities for conidial production on infected adult cadavers. Two strains stood out, B. bassiana IBCB-240 and M. anisopliae IBCB-364, as especially lethal for ESB adults under laboratory conditions, sporulated abundantly on infected insects, and also outperformed comparable strains used in commercial mycoinsecticides. Notably, B. bassiana IBCB-240 exhibited lower LT values at low inoculum levels (≤ 10 conidia mL) and smaller LC values than M. anisopliae IBCB-364. Taken together, this study emphasizes natural variation in virulence among indigenous Beauveria and Metarhizium strains against ESB adults and identifies fungal strains with superior lethality to existing commercialized strains for managing this eucalyptus pest in Brazil.
桉树象鼻虫（ESB），Gonipterus platensis，是澳大利亚特有的，但已成为巴西桉树种植园的主要入侵性、破坏性害虫。基于昆虫病原真菌开发针对 ESB 的杀虫剂的努力受到缺乏已知的高毒力菌株的限制。因此，我们探索了巴西本土的几种主要昆虫病原真菌 - 球孢白僵菌和金龟子绿僵菌对 ESB 成虫的毒力。我们发现，感染成年尸体后的毒力和后期产孢能力存在广泛差异。两种菌株 B. bassiana IBCB-240 和 M. anisopliae IBCB-364 特别对 ESB 成虫具有致死性，在感染昆虫上大量产孢，而且性能优于商业用的类似菌株。值得注意的是，B. bassiana IBCB-240 在低接种量（≤10 个分生孢子/mL）下表现出较低的 LT 值，并且 LC 值低于 M. anisopliae IBCB-364。总的来说，这项研究强调了针对 ESB 成虫的巴西本土白僵菌和绿僵菌菌株之间毒力的自然变异，并确定了具有比现有商业化菌株更高致死性的真菌菌株，可用于管理巴西的这种桉树害虫。
