Eco-friendly synthesized copper nanoparticles from Platostoma menthoides (L.): A novel bio larvicidal strategy against Spodoptera frugiperda

The green synthesis of copper nanoparticles (CuNPs) using an aqueous extract from a medicinal plant, Platostoma menthoides was investigated, emphasizing its larvicidal properties. This study aimed to evaluate the efficacy of these green-synthesized copper nanoparticles as a sustainable larvicidal agent against pest control agents. The biosynthesized CuNPs were thoroughly characterized through various analytical techniques, including UV–Vis spectroscopy, FT–IR, XRD, SEM, EDAX, particle size analysis and zeta potential, and HR-TEM. The successful synthesis of CuNPs was confirmed by the presence of an absorbance peak at 343 nm. FT–IR spectra identified various functional groups and molecular interactions, while XRD analysis revealed their crystalline nature. SEM analysis confirmed the cubic morphology of the nanoparticles, and EDAX determined the elemental copper composition. Particle size analysis indicated an average size of 152.3 nm and a zeta potential of −34.6 mV affirmed their stability. CuNPs exhibiting crystalline morphology and moderate aggregation, as confirmed by HR-TEM analysis. Potent larvicidal activity against Spodoptera frugiperda was observed. A dosage of 100 μg/mL resulted in LC₅₀ and LC₉₀ values of 55.64 and 122.79 μg/mL, respectively, at 24 h post-treatment. Histopathological analysis of larvae treated with nanoparticles revealed extensive tissue damage and structural disruption. Furthermore, a Lethality bioassay using Artemia salina nauplii showed a dose-dependent toxic response was observed with 100 μg/mL showing an LC₅₀ and LC₉₀ value of 165.59 and 247.73 μg / mL, indicating that the CuNPs exhibit moderate toxicity. These findings highlight the potential of P. menthoides-derived CuNPs as an eco-friendly pest control agent with promising applications in sustainable agriculture and pest management.