Chikungunya, dengue, Zika, malaria, Japanese encephalitis, filariasis, West Nile, etc. are mosquito transmitted diseases that have killed millions of people worldwide, and millions of people are at risk of these diseases. Control of the mosquitoes, such as Aedes aegypti and Culex quinquefasciatus, is challenging due to their development of resistance to synthetic insecticides. The habitats of the young mosquitoes are also the habitats for foodborne pathogens like Staphylococcus aureus (MTCC96) and Serratia marcescens (MTCC4822). The present study was aimed at synthesizing eco-friendly green nanoparticles using Dillenia indica leaf broth and analyzing its efficacy in controlling the vector mosquitoes A. aegypti and C. quinquefasciatus, as well as the microbial pathogens St. aureus and Se. marcescens. The formation of selenium nanoparticles (SeNps) was confirmed using UV-Vis spectroscopy (absorption peak at 383.00 nm), Fourier transform infrared radiation (FTIR spectrum peaks at 3177, 2114, 1614, 1502, 1340, 1097, 901, 705, and 508 cm−1), X-ray diffraction (diffraction peaks at 23.3 (100), 29.6 (101), 43.5 (012), and 50.05 (201)), and scanning electron microscopy (oval shaped). The size of the nanoparticles and their stability were analyzed using dynamic light scattering (Z-Average value of 248.0 nm) and zeta potential (−13.2 mV). The SeNps disorganized the epithelial layers and have broken the peritrophic membrane. Histopathological changes were also observed in the midgut and caeca regions of the SeNPs treated A. aegypti and C. quinquefasciatus larvae. The SeNps were also active on both the bacterial species showing strong inhibitory zones. The present results will explain the ability of SeNps in controlling the mosquitoes as well as the bacteria and will contribute to the development of multi potent eco-friendly compounds.

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Development of resistant in vectors especially vector mosquitoes are becoming a challenge for the scientific community for management and control mosquito population. Vector mosquitoes are likely to withstand toxicity and develop resistant mechanism to single active compound hence, combining medicinal plants with rich active compounds stops resistant development and proliferation of mosquitoes. In this study we put effort to evaluate the effect of methanol extract of Tagetes patula, Clerodentron phillomedis, and Catharanthus roseus in individual and in combination against the dengue vector, Stegomyia agyptii. Lethal concentrations (LC50 and LC90) were calculated to find out the effect of the test plants in individual and in combination. T. patula extract showed vaguely higher mortality rate when compared to C. phillomedis, and C. roseus but there was no significant variation among the three test plants. The median LC of combined treatment showed a significant difference between the combined (2.25 mg/mL/3 rd instar) and individual treatment (6.41 mg/mL/3 rd instar for T. patula, 6.85 mg/mL/3 rd instar for C. phillomedis and 6.59 mg/mL/3 rd instar for C. roseus). The combined efficacy of three test plants was also effective in controlling vector mosquitoes at fields with different agro-climatic conditions. The study proves that the combination of T. patula, C. phillomedis, and C. roseus is effective in different field conditions at lower concentrations.

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Mangifera indica is an important commercial fruit of India and primary food source for the mango leafhopper, Amritodus brevistylus further leading to the development of its associated fungus, Aspergillus niger. The present study was done to assess the antifungal and insecticidal activity of biologically synthesized silver nanoparticles using peel extracts of Raphanus sativus (Brassicaceae). Raphanus sativus peel extract is effective in extracellular reduction of Ag ions and capping the synthesized nanoparticles avoiding further agglomeration. The synthesized AgNPs are characterized by UV-vis spectroscopy, X-ray diffraction analysis, fourier transform infrared spectroscopy, scanning electron microscopy and energy dispersive x-ray analysis. Biologically synthesized AgNPs exhibited significant toxicity (LC50 − 7.61 ppm/48h) over mango leafhopper, Amritodus brevistylus. Silver nanoparticles synthesized using Raphanus sativus is also effective against the fungal pathogen, Aspergillus niger (developed on the infestations of mango leafhopper, Amritodus brevistylus) showing very strong inhibitory zone (80 mm).

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Aedes aegypti, the dengue vector, is a menace continuing since 1780; it is due to development of resistant to synthetic insecticides and Staphylococcus aureus, the common microbial pathogen agent of food poisoning, skin infections and respiratory infections have developed multidrug resistant, which forced us to focus on novel agent for which the dengue vector and bacterial pathogen have not practiced to develop resistant and which cannot detoxify it using its usual enzyme activity as it did earlier. Silver nanoparticles a challenging insecticidal agents for the toxic degrading enzymes of both the insect and microbe was the target of our present study to excavate the potential in killing immature of dengue vector and bacterial pathogen. Green protocolled nanoparticles were successfully synthesized using leaf extract of Nilgirianthus ciliatus which act as reducing as well as capping agents. The UVvis spectra observed at 441nm confirmed the presence of silver nanoparticles. XRD and FT-IR confirmed the crystalline nature and organic capping around the silver nanoparticles respectively. SEM and DLS showed the average size at 117 nm and the particle dispersion was at -17.2mV zeta potential.