Moderately susceptible tomato cultivar S. navodhya was used to determine the efficacy of nanoparticles on seedling growth using standard method with some modifications [31]. Briefly, tomato seeds were surface sterilized by immersing in 10% sodium hypochlorite solution for 10 min and then rinsed thrice with deionized water. The sterilized seeds were placed in Petri plates (90 × 15 mm, HiMedia, Mumbai, India), having filter paper wet with 5.0 ml deionized water as control and 5.0 ml of different concentrations (0.08, 0.10 and 0.12%, w/v,) of Cu–chitosan NPs along with chitosan 0.1% and CuSO4 0.1%. Each treatment was performed in triplicates with 10 seeds in each plate. Sealed Petri plates were maintained at 28 ± 2 °C in a dark growth room. Data were recorded for seed germination percentage, mean seedling length and fresh and dry weight after 10-days. Seedling vigor index (SVI) was calculated by the formula described by Abdul-Baki and Anderson [32]. Seed vigor index = (germination %) × (seedling length)