School of Biodiversity, One Health, and Veterinary Medicine, University of Glasgow, Glasgow, United Kingdom.
Department of Zoology, Cotton University, Guwahati, Assam, India.
PLoS One. 2024 Sep 6;19(9):e0308707. doi: 10.1371/journal.pone.0308707. eCollection 2024.
Vector-borne diseases resulted into several cases of human morbidity and mortality over the years and among them is filariasis, caused by the mosquito Culex quinquefasciatus. Developing novel strategies for mosquito control without jeopardizing the environmental conditions has always been a topic of discussion and research. Integrated Vector Management (IVM) emphasizes a comprehensive approach and use of a range of strategies for vector control. Recent research evaluated the use of two entomopathogenic fungi; Beauveria bassiana and Lecanicillium lecanii in IVM, which can serve as potential organic insecticide for mosquito population control. However, their combined efficacy has not yet been evaluated against mosquito control in prior research and a gap of knowledge is still existing. So, this research was an attempt to bridge up the knowledge gap by (1) Assessing the combined efficacy of Beauveria bassiana and Lecanicillium lecanii on Culex quinquefasciatus (2) To investigate the sub-lethal concentration (LC50) of the combined fungal concentration and (3) To examine the post-mortem effects caused by the combined fungal concentration under Scanning Electron Microscope (SEM). The larval pathogenicity assay was performed on 4th instar C. quinquefasciatus larvae. Individual processed fungal solution of B. bassiana and L. lecanii were procured and to test the combined efficacy, the two solutions were mixed in equal proportions. To evaluate the sub-lethal concentration (LC50), different concentrations of the combined fungal solution were prepared by serial dilations. The mortality was recorded after 24 hours for each concentration. Upon treatment and evaluation, The LC50 values of B. bassiana and L. lecanii were 0.25 x 104 spores/ml and 0.12 x 104 spores/ml respectively and the combined fungal concentration was 0.06 x 103 spores/ml. This clearly indicated that the combined efficacy of the fungi is more significant. Further, SEM analysis revealed morphological deformities and extensive body perforations upon combined fungal treatment. These findings suggested that combining the two fungi can be a more effective way in controlling the population of Culex quinquefasciatus.
多年来，虫媒病导致了几个人类发病和死亡的病例，其中包括由库蚊 Culex quinquefasciatus 引起的丝虫病。开发新型的蚊子控制策略而不危及环境条件一直是讨论和研究的主题。综合蚊子管理 (IVM) 强调了一种全面的方法和使用一系列策略来进行蚊子控制。最近的研究评估了两种昆虫病原真菌——球孢白僵菌和淡紫拟青霉在 IVM 中的应用，它们可以作为潜在的有机杀虫剂来控制蚊子种群。然而，在之前的研究中，它们联合使用的效果尚未得到评估，知识空白仍然存在。因此，这项研究试图通过以下方式来填补这一知识空白：(1) 评估球孢白僵菌和淡紫拟青霉对库蚊的联合效果；(2) 研究联合真菌浓度的亚致死浓度 (LC50)；(3) 通过扫描电子显微镜 (SEM) 检查联合真菌浓度引起的死后效应。幼虫致病性试验在 4 龄期库蚊幼虫上进行。单独获取球孢白僵菌和淡紫拟青霉的处理真菌溶液，并将两种溶液按等比例混合以测试联合效果。为了评估亚致死浓度 (LC50)，通过连续稀释制备不同浓度的联合真菌溶液。对每个浓度的死亡率在 24 小时后进行记录。经过处理和评估，球孢白僵菌和淡紫拟青霉的 LC50 值分别为 0.25 x 104 孢子/ml 和 0.12 x 104 孢子/ml，联合真菌浓度为 0.06 x 103 孢子/ml。这清楚地表明真菌的联合效果更显著。此外，SEM 分析显示，在联合真菌处理后，形态发生畸形和广泛的身体穿孔。这些发现表明，联合使用这两种真菌可能是控制库蚊种群的更有效方法。
