In present research work, silver nanoparticles were biosynthesized using quick, economical method and possibilities of using nanoparticles against phytopathogens were evaluated. Silver NPs were synthesized by simple and quick, microwave assisted method using fruit peel extract of citrus hybrid “Kinnow”. Synthesized NPs were characterized using UV visible spectroscopy, particle size analyzer and transmission electron microscope. Small sized, stable silver nanoparticles in the size range of 18–55 nm were synthesized. Antimicrobial activity against three phytopathogens i. e. Alternaria solani, Thanatephorus cucumeris and Botryodiplodia theobromae were studied and showed effective potential against all the fungal pathogens under in vitro conditions. Efficient control against early blight was observed during pot study preventing outbreak of disease in tomato plants.