The invincible effects of the entomopathogenic fungi (EPF) under appropriate circumstances compensate for the flaws of chemical insecticides in the control programs. Beauveria bassiana is one of the most elaborated EPF of pest control all over the world. The potential of using the B. bassiana isolate (Y-F_ITS1) was examined against different larval instars (L2, L3, L4, and L5), pupae, and eggs of the cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae), using different concentrations under laboratory conditions. In bioassay, 2nd instar larvae of S. littoralis were significantly the most susceptible stage to B. bassiana isolate at P ≤ 0.05. It is apparent from the results that the cumulative mortality percentage increased with elapsing time with typical symptoms of infection and sporulation. High efficacies ranging from 85.0 to 99.0% corrected mortality rates were recorded for 2nd instar larvae at the spore concentration (1 × 109 spores ml−1). The mortality percentage reached 90.0% for the 3rd instar larvae treated with the same concentration after 5 days. The least mortality rates results were recorded at the 5th instar larvae. B. bassiana isolate showed an ovicidal effect to the eggs of S. littoralis that reached 100% mortality when treated with 1.0 × 108 and 1.0 × 109 spores ml−1, while the concentration 1 × 107 and 1.0 × 108 caused 65.0 and 87.0%, respectively. Reduction of adult emergence reached (0%) in case of treatment with the highest concentrations (1 × 108 and 1 × 109 spores ml−1). Morphogenetic abnormalities were also recorded. Results of mortality rates and lethal concentration values resulted from the experiments indicated that the tested Y-F_ITS1 isolate was efficient and can be recommended as a potential biocontrol agent against S. littoralis. Further field evaluations are still needed.

中文翻译：

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在实验室条件下，本地球孢白僵菌分离株在棉叶虫斜纹夜蛾（Boisduval）（鳞翅目：夜蛾科）不同生命阶段的致病性。

在适当情况下，昆虫病原性真菌（EPF）的无敌作用弥补了控制程序中化学杀虫剂的缺陷。球孢白僵菌是全世界最详尽的害虫防治EPF之一。对棉铃虫，斜纹夜蛾（Boisd。）（鳞翅目：夜蛾科）的不同幼虫（L2，L3，L4和L5）幼虫（L2，L3，L4和L5），p和卵检查了使用芽孢杆菌分离物（Y-F_ITS1）的潜力。 ），在实验室条件下使用不同的浓度。在生物测定中，滨海链球菌的第二龄幼虫明显是B. bassiana分离株的最易感阶段，P≤0.05。从结果可以明显看出，随着时间的流逝，典型的感染和孢子形成症状使累积死亡率增加。效率从85不等。在孢子浓度（1×109孢子ml-1）下，第二龄幼虫的校正死亡率为0至99.0％。5天后用相同浓度处理的三龄幼虫的死亡率达到90.0％。第五龄幼虫记录的死亡率最低。球芽孢杆菌分离株对沿海链球菌的卵具有杀卵作用，用1.0×108和1.0×109孢子ml-1处理可达到100％的死亡率，而浓度1×107和1.0×108引起65.0和87.0％ ， 分别。在最高浓度（1×108和1×109孢子ml-1）的情况下，成人出苗率降低（0％）。还记录了形态发生异常。实验得出的死亡率和致死浓度值的结果表明，所测试的Y-F_ITS1分离物是有效的，可以推荐作为抗滨海链球菌的潜在生物防治剂。仍然需要进一步的现场评估。