The diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a noxious pest of cruciferous crops all over the world causing serious economic damage. Management of insect pest generally depends on chemical control; however, due to development of resistance against all types of insecticides, alternative approaches especially utilization of a microbial agent is inevitable. Potential of 2 entomopathogenic fungi (EPF), viz., Beauveria bassiana and Metarhizium anisopliae, was evaluated against 2nd and 3rd larval instars of P. xylostella by adopting leaf dip and direct spraying methods under laboratory conditions. Significant mortality rate was achieved by each fungus under adopted methodologies. However, B. bassiana was found to be more effective in both conditions than M. anisopliae. Highest mean corrected mortality (77.80%) was recorded, when spores of B. bassiana were sprayed on the 2nd instar larvae (LC50=1.78×104/ml) after the 6th day of treatment. Similarly, incase of M. anisopliae LC50 for the 2nd instar at the same methodology was 2.78×104/ml with a mortality percentage of 70.0%. Offspring sex ratio was non-significantly related to treatment concentration and methodology, except for the control. Beauveria bassiana and M. anisopliae had potential to suppress P. xylostella infestations when applied appropriately. Present findings suggested that B. bassiana and M. anisopliae when sprayed on immatures of host insect had more effect as compared to leaf dip procedure. Furthermore, no significant effect of concentrations was observed on sex ratio.

中文翻译：

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关于昆虫病原真菌白僵菌和绿僵菌（子囊菌门：Hypocreales）对小菜蛾小菜蛾小菜蛾（L.）（鳞翅目：小菜蛾科）的毒力

小菜蛾Plutella xylostella (L.) (Lepidoptera: Plutellidae) 是世界范围内十字花科作物的一种有害害虫，对经济造成严重破坏。虫害的管理一般依赖于化学防治；然而，由于对所有类型杀虫剂的抗药性的发展，替代方法尤其是微生物制剂的利用是不可避免的。在实验室条件下，采用浸叶和直接喷洒的方法，评估了 2 种昆虫病原真菌 (EPF)，即白僵菌和绿僵菌对小菜蛾 2 和 3 龄幼虫的潜力。在采用的方法下，每种真菌都实现了显着的死亡率。然而，发现 B. bassiana 在这两种情况下都比 M. anisopliae 更有效。最高平均校正死亡率 (77. 80%) 记录，当在第 6 天处理后将球孢子虫孢子喷洒在 2 龄幼虫上时 (LC50=1.78×104/ml)。类似地，在相同的方法中，二龄的 M. anisopliae LC50 为 2.78×104/ml，死亡率为 70.0%。除对照外，后代性别比与处理浓度和方法无显着相关。白僵菌和绿僵菌在适当应用时具有抑制小菜蛾侵染的潜力。目前的研究结果表明，与浸叶程序相比，将 B. bassiana 和 M. anisopliae 喷洒在寄主昆虫的幼虫上时具有更大的效果。此外，没有观察到浓度对性别比的显着影响。类似地，在相同的方法中，二龄的 M. anisopliae LC50 为 2.78×104/ml，死亡率为 70.0%。除对照外，后代性别比与处理浓度和方法无显着相关。白僵菌和绿僵菌在适当应用时具有抑制小菜蛾侵染的潜力。目前的研究结果表明，与浸叶程序相比，将 B. bassiana 和 M. anisopliae 喷洒在寄主昆虫的幼虫上时具有更大的效果。此外，没有观察到浓度对性别比例的显着影响。类似地，在相同的方法中，二龄的 M. anisopliae LC50 为 2.78×104/ml，死亡率为 70.0%。除对照外，后代性别比与处理浓度和方法无显着相关。白僵菌和绿僵菌在适当应用时具有抑制小菜蛾侵染的潜力。目前的研究结果表明，与浸叶程序相比，将 B. bassiana 和 M. anisopliae 喷洒在寄主昆虫的幼虫上时具有更大的效果。此外，没有观察到浓度对性别比的显着影响。除了控制。白僵菌和绿僵菌在适当应用时具有抑制小菜蛾侵染的潜力。目前的研究结果表明，与浸叶程序相比，将 B. bassiana 和 M. anisopliae 喷洒在寄主昆虫的幼虫上时具有更大的效果。此外，没有观察到浓度对性别比例的显着影响。除了控制。白僵菌和绿僵菌在适当应用时具有抑制小菜蛾侵染的潜力。目前的研究结果表明，与浸叶程序相比，将 B. bassiana 和 M. anisopliae 喷洒在寄主昆虫的幼虫上时具有更大的效果。此外，没有观察到浓度对性别比例的显着影响。