Fabrication and characterization of Calotropis procera-mediated Iron oxide nanoparticles and assessment of their pesticidal potential

The infestation of pests has emerged as a paramount concern in agriculture arenas. To contend with these challenges, nanotechnology has been booming as a viable approach; as utilization of synthetic pesticides has conferred multiple inadequacies i.e. diminished eco-stability, laborious manufacturing, substantial pesticidal resistance and safety concerns. This study aims to optimize a green method for synthesizing ferric oxide nanoparticles (Fe 2 O 3 -NPs) as an effective nano-biopesticide against phytopathogenic pests. Various synthesis parameters including salt concentration, temperature, pH, and stirring time were optimized using Response Surface Methodology (RSM). Characterization of formed Fe 2 O 3 NPs was done via UV-visible spectroscopy, zetasizer, zeta potential, FTIR, SEM, TEM, XRD and VSM analysis. LC-ESI-MS/MS analysis of C. procera extract unveiled the presence of multiple unidentified metabolites and FTIR analysis has further validated their reductant and stabilizing role in Fe 2 O 3 formulations. VSM analysis confirmed the anti-ferromagnetic nature of hematite phase of Iron oxide NPs. Spherically morphed Fe 2 O 3 NPs with surface potential of -31.54 mV and particle size of 58.09 nm exhibited UV-visible bands at 215 nm. In pursuit of pesticidal determination, ferric oxide NPs exhibited more mortality rate (73.00±1.80 %) against Oryzaephilus surinamensis as compared to Tribolium castaneum (71.5±1.41 %) at the highest concentration of 200 mg/ml. Toxicological analysis disclosed the non-mutagenicity of biosynthesized iron oxide NPs. In pot trials, Iron oxide NPs have shown substantial improvement in growth parameters of plants at highest concentrations. Thus, the findings of this study demonstrated C. procera extract based Fe 2 O 3 NPs as an efficient and eco-friendly strategy to kill plant pests.