Entomology Division, Nepal Agricultural Research Council, Khumaltar, Lalitpur, Nepal.
Department of Bioresource Sciences, Andong National University, Andong, Republic of Korea.
PLoS One. 2018 Apr 17;13(4):e0195848. doi: 10.1371/journal.pone.0195848. eCollection 2018.
A strain (ARP14) of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin was isolated from field-collected Riptortus pedestris (Fabricius) (Hemiptera: Alydidae). The lethal median concentration of the ARP14 strain was compared with that of a commercialized strain (GHA) of the same fungus against R. pedestris and its two egg parasitoids, Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead) (Hymenoptera: Platygastridae). Mortality and mycosis rates were evaluated after exposure to five concentrations of the fungus, i.e., 1×109, 1×108, 1×107, 1×106, and 1×105 conidia/mL, using a glass scintillation vial as an exposure arena in 25.0 ± 0.5°C and 93.7 ± 2.9% RH. The lethal median concentrations (LC50) for 2nd and 4th instar nymphs, and adults of R. pedestris were not significantly different between the two strains of B. bassiana. However, the mycosis rate of ARP14 was 1.3 and 1.8 times higher than that of the GHA strain in 4th instar nymphs and adult females of R. pedestris, respectively, at the 1×108 conidia/mL concentration. More interestingly, the mycosis rates at 1×108 conidia/mL concentration in the parasitoids G. japonicum and O. nezarae were much lower in the ARP14 strain (15.0 and 0%) than in the GHA strain (73.3 and 66.0%), respectively, suggesting that the B. bassiana strain ARP14 is less virulent to these parasitoids than the commercially available strain. Our results suggest that B. bassiana ARP14 may be a potential new biopesticide against R. pedestris with fewer negative effects on beneficial parasitoids than currently available options.
从田间采集的直纹稻弄蝶（Riptortus pedestris）（半翅目： Alydidae）中分离出一株球孢白僵菌（Beauveria bassiana）（Balsamo）Vuillemin 的菌株（ARP14）。比较了 ARP14 菌株与同一真菌的商业化菌株（GHA）对直纹稻弄蝶及其两种卵寄生蜂，Ooencyrtus nezarae Ishii（膜翅目：Encyrtidae）和 Gryon japonicum（Ashmead）（膜翅目： Platygastridae）的致死中浓度。在 25.0±0.5°C 和 93.7±2.9%RH 下，将五种浓度的真菌（1×109、1×108、1×107、1×106 和 1×105 个孢子/mL）暴露在玻璃闪烁小瓶中作为暴露场，评估死亡率和真菌病发生率。直纹稻弄蝶 2 龄和 4 龄若虫以及成虫的致死中浓度（LC50）在两种球孢白僵菌菌株之间没有显著差异。然而，在 1×108 个孢子/mL 浓度下，ARP14 菌株在直纹稻弄蝶 4 龄若虫和雌成虫中的真菌病发生率分别比 GHA 菌株高 1.3 和 1.8 倍。更有趣的是，在 1×108 个孢子/mL 浓度下，寄生蜂 G. japonicum 和 O. nezarae 的真菌病发生率在 ARP14 菌株中明显低于 GHA 菌株（分别为 15.0%和 0%），这表明与市售菌株相比，B. bassiana 菌株 ARP14 对这些寄生蜂的毒力较低。我们的研究结果表明，与目前可用的选项相比，B. bassiana ARP14 可能是一种针对直纹稻弄蝶的潜在新型生物农药，对有益的寄生蜂的负面影响较小。
