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Erythrina variegata (E. variegata) bioactive chemical has been the potential to be utilized as a good, eco-friendly approach for the control of mosquito population. In the present investigation, methanol extract using insecticidal compounds isolated against mosquito larvae kill assay was carried out. Secondary metabolism was characterized by thin layer chromatography, column chromatography, Fourier transform-infrared spectroscopy, gas chromatography-mass spectral, and identification of compound. Mosquito immature third instar larval, Anopheles stephensi, and Culex quinquefasciatus have been exposed to different concentrations of 50-250 µg/ml. Totally, larvae were death rate 98.2% (significant value 0.001b) from methanol extract and it is significant toxicity against larvae of An. stephensi and Cx. quinquefasciatus with LC50/LC99 values were 157.69/339.55 µg/ml and 137.67/297.33 µg/ml, respectively. FT-IR analysis in the functional groups such as alcohol, amines, amides, alkenes, 1⁎ amines, aromatic amines, aliphatic amines, 1⁎,2⁎ amines, and alkyl halides searched the identity of secondary metabolites, which may act as 12-Octadecenoic acid, methyl ester compound and clearly indicates being phytochemical. Chemical constituents of twenty-five compounds were identified in the methanol extract. The major components were 12-Octadecenoic acid and methyl ester (37.31%). Compound molecules consist of carbon 19 atoms (gray), hydrogen 36 atoms (greenish blue), and oxygen 2 atoms (red), indicated by the different colors. The results were obtained suggesting that, in addition to their pharmaceutical and medicine sources, 12-Octadecenoic acid, methyl ester compound can also serve as a natural mosquito control.

Mosquitoes are the most critical group of insects in the context of public health, since they transmit key parasites and pathogens, causing millions of deaths annually. Aedes albopictus is an important invasive mosquito vector of dengue fever across urban and semiurban areas of India. In this study, we biofabricated silver nanoparticles (AgNPs) using the Fimbristylis miliacea aqueous leaf extract (Fm-ALE) as reducing and stabilizing agent. The synthesis of Fm-AgNPs was confirmed by the excitation of surface plasmon resonance and orange-brown color using ultraviolet-visible (UV-vis) spectrophotometry. High-resolution scanning electron microscopic (HR-SEM) and transmission electron microscopic (TEM) showed the clustered (size 0.5 μm) and quasi-spherical structures of Fm-AgNPs. The formation of AgNPs has been characterized by X-ray diffraction (XRD) spectroscopy. Fourier transform infrared (FTIR) spectroscopy investigated the identity of secondary metabolites, which may act as Fm-AgNP capping agents. These results propose that AgNPs synthesized provided from those Fm-ALE have the high sources to be improved into the most suitable materials useful for protecting and killing the invasive mosquito vector, Ae. albopictus populations. The acute toxicity of Fm-ALE synthesized Ag NPs, and a combined treatment testing blends of mosquito vector was evaluated against I, II, III, and IV instar larva’s (ILs) of Ae. albopictus. The LC50 values of Fm-ALE (174.39 ppm I-ILs, 214.40 ppm II-ILs, 232.38 ppm III-ILs, and 251.62 ppm IV-ILs) and Fm-AgNPs synthesized were 23.78 ppm I-ILs; 27.88 ppm II-ILs; 31.47 ppm III-ILs; 36.68 ppm IV-ILs, respectively. Likewise, Fm-AgNP synthesis was more toxic than ALE in the invasive mosquito vector and recorded from UV-vis spectrum, FTIR, TEM, and XRD analysis. These results propose that AgNPs synthesized provided from those Fm-ALE have the high sources to be improved into the most suitable materials useful for protecting and killing the invasive mosquito vector, Ae. albopictus populations.