Ni Nian-Tong, Wu Sing-Shan, Liao Kuei-Min, Tu Wu-Chun, Lin Chuen-Fu, Nai Yu-Shin
Department of Entomology, National Chung Hsing University, Taichung 402, Taiwan.
National Mosquito-Borne Diseases Control Research Center, National Health Research Institutes, Tainan 704, Taiwan.
J Fungi (Basel). 2022 Aug 16;8(8):861. doi: 10.3390/jof8080861.
(Diptera: Ceratopogonidae) is a nuisance blood-sucking pest to humans in Taiwan. An bite causes itching and redness and usually causes serious harassment to human outdoor activity. In terms of control, chemical pesticides are ineffective. Therefore, other efforts are needed. Fungal mycosis in the larvae, pupae, and emerging adults was found during the rearing of . In this study, six fungal isolates were isolated from infected cadavers and subjected to molecular identification. In addition, their biocontrol potential was evaluated against different life stages of Based on the pathogenicity screening, two fungal isolates, NCHU-NPUST-175 and -178, which caused higher mortality on the fourth instar larvae of , were selected for virulence tests against different life stages of larvae. The results of the phylogenetic analysis indicated that the NCHU-NPUST-175 and -178 belonged to and , respectively. Bioassay against different life stages of with different spore concentrations (5 × 10 to 5 × 10 conidia/mL) revealed a dose-dependent effect on larvae for both fungal isolates, while only 38% and 50% mortality was found in highest concentration (5 × 10 conidia/mL) at fourth instar larvae by Pl-NCHU-NPUST-175 and Fv-NCHU-NPUST-178, respectively. Moreover, reductions in egg-hatching rate and adult emergence rate were found, when the last stage of was inoculated with both fungal isolates, indicating the ovicidal potential and the impact of entomopathogenic fungi on the development of . In conclusion, Pl-NCHU-NPUST-175 and Fv-NCHU-NPUST-178 showed larvicidal activity, ovicidal activity, and impact on adult emergence on .
（双翅目：蠓科）是台湾地区对人类有害的吸血害虫。蠓虫叮咬会引起瘙痒和红肿，通常会严重干扰人类的户外活动。在蠓虫防治方面，化学杀虫剂效果不佳。因此，需要其他防治措施。在蠓虫饲养过程中，发现其幼虫、蛹和羽化后的成虫存在真菌病。在本研究中，从受感染的虫尸中分离出6株真菌菌株，并进行分子鉴定。此外，还评估了它们对蠓虫不同发育阶段的生物防治潜力。基于致病性筛选，选择了对蠓虫四龄幼虫致死率较高的两株真菌菌株NCHU-NPUST-175和-178，对蠓虫幼虫的不同发育阶段进行毒力测试。系统发育分析结果表明，NCHU-NPUST-175和-178分别属于和。用不同孢子浓度（5×10至5×10分生孢子/毫升）对蠓虫不同发育阶段进行生物测定，结果显示这两株真菌菌株对幼虫均有剂量依赖性影响，而在最高浓度（5×10分生孢子/毫升）下，Pl-NCHU-NPUST-175和Fv-NCHU-NPUST-178对蠓虫四龄幼虫的致死率分别仅为38%和50%。此外，当用这两株真菌菌株接种蠓虫的最后阶段时，发现其卵孵化率和成虫羽化率降低，表明昆虫病原真菌具有杀卵潜力以及对蠓虫发育的影响。总之，Pl-NCHU-NPUST-175和Fv-NCHU-NPUST-178对蠓虫表现出杀幼虫活性、杀卵活性以及对成虫羽化的影响。
