Synthesis of silver nano particles following green protocols is an emerging area of interest throughout the world, as it has multiple applications in different fields. Moreover the methods are non-toxic, sustainable, eco-friendly and economically viable ones. In the current work, that we have presented is an approach towards the development of zero cost and eco-friendly approach for the preparation of nanoparticles following the green route, using the leaf extract of Vitex negundo, a common medicinal plant in South India. The specific phenomenon of Surface Plasmon Resonance (SPR) has been used for the depiction of the silver nano particles prepared. The silver nanoparticles created was characterized by using UV-Visible Spectroscopy and its performance towards the naked eye detection of several heavy metal ions was done. The larvicidal activity of silver nano particles were assessed as per the standards prescribed by WHO.