Abstract Entomopathogenic fungi (EPF) can be viable options for biological control of agricultural pests. The selection of fungal strains is crucial for a successful pest control. The current study aimed to determine in the laboratory the susceptibility of different immature stages of Duponchelia fovealis Zeller (Lepidoptera: Crambidae) to EPF strains (Beauveria bassiana Bea111 and Cordyceps javanica Isa340). Immature stages of D. fovealis were sprayed with EPF concentrations from 2 × 103 to 2 × 109 conidia mL−1 and their viability and mortality were evaluated. Lethal time and concentration were estimated for pupae and each larval instar. Virulence depended on strain, dose, and insect life stage. The eggs were resistant to Bea111 and Isa340 strains. Mortality of larvae depended on the EPF strain and the larval instar, with the first instar being the most sensitive. Lethal concentrations for D. fovealis 1st instar larvae were 3.4 × 105 and 1.7 × 107 conidia mL−1 with Bea111 and Isa340, respectively. Isa340 performed better than Bea111 for controlling pupae. Scanning electron microscopy revealed the adhesion and penetration structures of both fungi in the 2nd instar infected larvae 6 h after inoculation, while fungal extrusion occurred between 54 and 94 h after spraying with Bea111 and Isa340, respectively.

中文翻译：

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球孢白僵菌和虫草在不同未成熟阶段对杜蓬小球藻（鳞翅目：蟹科）的侵染

摘要 昆虫病原真菌 (EPF) 是农业害虫生物防治的可行选择。真菌菌株的选择对于成功控制害虫至关重要。目前的研究旨在在实验室中确定不同未成熟阶段的 Duponchelia fovealis Zeller（鳞翅目：蟹科）对 EPF 菌株（Beauveria bassiana Bea111 和 Cordyceps javanica Isa340）的敏感性。用 2 × 103 至 2 × 109 分生孢子 mL-1 的 EPF 浓度喷洒 D. fovealis 的未成熟阶段，并评估它们的生存力和死亡率。估计蛹和每个幼虫龄期的致死时间和浓度。毒力取决于品系、剂量和昆虫生命阶段。这些鸡蛋对 Bea111 和 Isa340 菌株具有抗性。幼虫的死亡率取决于 EPF 菌株和幼虫龄期，一龄是最敏感的。D. fovealis 1 龄幼虫的致死浓度分别为 3.4 × 105 和 1.7 × 107 分生孢子 mL-1，Bea111 和 Isa340。Isa340 在控制蛹方面比 Bea111 表现更好。扫描电子显微镜显示接种后 6 h 的 2 龄感染幼虫中两种真菌的粘附和渗透结构，而真菌挤出发生在分别喷洒 Bea111 和 Isa340 后 54 至 94 h。