Zargham Faisal, Afzal Muhammad, Rasool Khadija, Manzoor Saba, Qureshi Naveeda Akhtar
Parasitology Lab, Department of Zoology, Faculty of Biological Sciences, Quaid-i-Azam University Islamabad, 45320, Pakistan.
Parasitology Lab, Department of Zoology, Faculty of Biological Sciences, Quaid-i-Azam University Islamabad, 45320, Pakistan; Entomology and Parasitology Lab, Department of Zoology, Faculty of Sciences, University of Sialkot, Daska Road Sialkot, 51040, Pakistan.
Exp Parasitol. 2023 Sep;252:108586. doi: 10.1016/j.exppara.2023.108586. Epub 2023 Jul 17.
Extensive fumigation of synthetic pesticides to control the mosquito vector during each post-monsoon season in Pakistan significantly enhanced the environmental contamination and extinction of beneficial insects from the urban ecosystems. In this context, the present study examined the larvicidal efficacy of green synthesized iron nanoparticles (IONPs), using an aqueous leaf extract of Grevillea robusta against the early 2nd and 4th instar larvae of Aedes aegypti and Anopheles stephensi in Pakistan. The prepared IONPs were characterized by UV-Vis spectrum, FTIR, X-ray diffraction, scanning electron microscopy, and energy-dispersive diffraction. Larvicidal bioassay was conducted at various concentrations (80, 160, 240, 320, and 400 ppm) of IONPs prepared from leaf extract of G. robusta, and readings were taken-every 12 h for two consecutive days. In vitro, larvicidal assay, G. robusta leaf extract IONPs exhibited high mortalities of 64-96% (LC = 259.07 ppm; LC = 443.92 ppm) for the second instar and 65-98% (LC = 238.05 ppm; LC = 433.93 ppm) for the fourth instar of Ae. aegypti, while in the case of An. stephensi 56-84% (LC = 297.96 ppm; LC = 528.69 ppm) for the second and 56-88% (LC = 292.72 ppm; LC = 514.00 ppm) mortality for fourth larvae at 12-48 h post-exposure times were observed respectively. Significant (p < 0.05) dose-dependent and exposure time-dependent trends were observed among the 2nd and 4th larvalinstar of An. stephensi and Ae. aegypti. However, both species showed similar response and observed no significant (p > 0.05) difference in percentage mortality between the vector mosquitoes An. stephensi and Ae. aegypti. Overall, this study demonstrates that the larvicidal efficacy of green synthesized IONPs at low concentrations can be an ideal eco-friendly and cost-effective biocontrol of vector mosquitoes' larvae of An. stephensi and Ae. aegypti.
在巴基斯坦，每年季风季节过后，为控制蚊虫媒介而广泛熏蒸合成农药，这显著加剧了环境污染，并导致城市生态系统中有益昆虫灭绝。在此背景下，本研究使用银桦树的水叶提取物，检测了绿色合成铁纳米颗粒（IONPs）对巴基斯坦埃及伊蚊和斯氏按蚊二龄初期和四龄幼虫的杀幼虫效果。通过紫外可见光谱、傅里叶变换红外光谱、X射线衍射、扫描电子显微镜和能量色散衍射对制备的IONPs进行了表征。使用从银桦树叶提取物制备的不同浓度（80、160、240、320和400 ppm）的IONPs进行杀幼虫生物测定，连续两天每12小时记录一次数据。在体外杀幼虫试验中，银桦树叶提取物IONPs对埃及伊蚊二龄幼虫的死亡率为64 - 96%（LC = 259.07 ppm；LC = 443.92 ppm），对四龄幼虫的死亡率为65 - 98%（LC = 238.05 ppm；LC = 433.93 ppm）；而对于斯氏按蚊，二龄幼虫死亡率为56 - 84%（LC = 297.96 ppm；LC = 528.69 ppm），四龄幼虫在暴露后12 - 48小时的死亡率为56 - 88%（LC = 292.72 ppm；LC = 514.00 ppm）。在斯氏按蚊和埃及伊蚊的二龄和四龄幼虫中观察到显著（p < 0.05）的剂量依赖性和暴露时间依赖性趋势。然而，两种蚊虫表现出相似的反应，在媒介蚊虫斯氏按蚊和埃及伊蚊之间的死亡率百分比上未观察到显著（p > 0.05）差异。总体而言，本研究表明，低浓度的绿色合成IONPs的杀幼虫效果可能是控制斯氏按蚊和埃及伊蚊幼虫的理想的生态友好且具有成本效益的生物防治方法。
