The banana stem weevil, Odoiporus longicollis (Olivier), is a serious threat to banana cultivation world over. Since banana is a food crop, the use of naturally infecting biological control agents could be an effective alternative to manage the insect pest instead of harmful chemicals. Also, the efficacy of entomopathogenic fungi against O. longicollis was used in bioassay. Among the Beauveria bassiana isolates tested the median lethal concentration (LC50) 10.468 × 105 conidia ml−1 when treated with B. bassiana (NRCBEFPMP1), two other isolates of B. bassiana, namely NRCBEPF22 and NRCBEPF2, were also effective against O. longicollis and recorded LC50 of 12.617 × 105 and 12.891 × 105 conidia ml−1, respectively. The results of bioassay with different Metarhizium spp. showed variations in efficacy, where the most virulent isolate was M. quizhouense (NRCBEPF11) with LC50 8.050 × 105 conidia ml−1. Scanning electron microscopic analysis showed that B. bassiana and M. quizhouense caused infection by cuticle penetration and completed the infection process in 15 days. The composition of volatile organic compounds released by B. bassiana and M. anisopliae during pathogenesis showed that a significantly high number of known insect volatiles were present in infected insects. Consequently, these volatiles were emission in Insect attractant, Odorant receptor agonist, Plant hormone Plant, and Microbial Metabolites, through the biological activity, such as Methyl salicylate, Benzaldehyde, alpha-Terpineol, Limonene, Benzene, 1,2-dimethoxy, Phthalic acid, 1-Octadecene, Phenylacetaldehyde, 3-Octanone, Octanal, Methylheptenone and 2-Ethyl-1-hexyl alcohol. Overall, the results show that EPF could significantly reduce damage by O. longicollis and produce a wide profile of secondary metabolites. Further, analysis was used for principal components to determine whether separated classes of fungi can be distinguished from one another based on their metabolite profiles.

中文翻译：

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昆虫病原真菌对香蕉假茎象鼻虫Odoiporus longicollis（Olivier）的作用及侵染过程阐明

香蕉茎象鼻虫 Odoiporus longicollis (Olivier) 对全世界的香蕉种植构成严重威胁。由于香蕉是一种粮食作物，因此使用具有自然感染性的生物防治剂可能是管理害虫而不是有害化学物质的有效替代方法。此外，昆虫病原真菌对 O. longicollis 的功效也用于生物测定。在用 B. bassiana (NRCBEFPMP1) 处理的白僵菌分离株中，测试的中位致死浓度 (LC50) 10.468 × 105 分生孢子 ml-1，另外两种 B. bassiana 分离株，即 NRCBEPF22 和 NRCBEPF2，也能有效对抗 O. longicollis并分别记录了 12.617 × 105 和 12.891 × 105 分生孢子 ml-1 的 LC50。不同绿僵菌的生物测定结果。显示出疗效的变化，其中毒性最强的分离株是 M. quizhouense (NRCBEPF11)，LC50 8.050 × 105 分生孢子 ml-1。扫描电镜分析显示，B. bassiana和M. quizhouense通过角质层穿透引起感染，15天完成感染过程。B. bassiana 和 M. anisopliae 在发病过程中释放的挥发性有机化合物的组成表明，受感染的昆虫中存在大量已知的昆虫挥发物。因此，这些挥发物通过生物活性释放到昆虫引诱剂、气味受体激动剂、植物激素植物和微生物代谢物中，如水杨酸甲酯、苯甲醛、α-松油醇、柠檬烯、苯、1,2-二甲氧基、邻苯二甲酸、1-十八烯、苯乙醛、3-辛酮、辛醛、甲基庚烯酮和2-乙基-1-己醇。全面的，结果表明，EPF 可以显着减少 O. longicollis 的损害并产生广泛的次级代谢物。此外，对主要成分进行了分析，以确定分离的真菌类别是否可以根据它们的代谢物谱相互区分。