This book gives a new deep insight on the insecticidal activity of the selenium nanoparticles bio fabricated from Pursulane targeting against Tuta absoluta a major pest on tomato plants. Insecticidal and larvicidal activity of selenium nanoparticles from plant based biofabrication proves that nanopesticide is a suitable candidate to fight and manage the agriculture pest in a ecofriendly, cost-effective manner.