Seaweed Lobophora variegata-based Silver Nanopesticide for environmental friendly management of economically important pest, Spodoptera litura

Faunal and floral-based silver nanoparticles (AgNPs) have been widely used in verities of fields due to their diverse properties. A simple, one step biogenesis of liquid AgNPs using a seaweed Lobophora variegata (Phaeophyta) thallus water extract at room temperature. Most of the NPs are oval shape (60%) than spherical shape (23%) with mean diameter ranged between 6.5 and 10 nm. The formation of L. variegata silver nanoparticles (LV-AgNPs) was confirmed with potentiometric titration and UV-visible spectrophotometer analyses. The XRD analysis of LV-AgNPs showed crystalline nature of AgNPs. The FT-IR narrow 3312 cm^-1 peak observed in the LV-AgNPs was characteristic of phenolic compounds indicates responsible for reduction, capping and stabilizing the LV-AgNPs. Moreover, the topography of the LV-AgNPs were analysed using TEM and EDX. Insecticidal activity of LV-AgNPs and the standard vijayneem (commercial neem product) against Spodotpera litura larvae showed similar impact. Lobophora variegata extract and LV-AgNPs affects development, moulting, morphology and protein profile suggest that the algae and its silver nanoparticle has potential to be used for eradicate the pest in the field.