Aphid infestation poses a significant threat to agricultural productivity, necessitating the development of eco-friendly and effective pest management strategies. In this study, we report the preparation, characterization, and insecticidal efficacy of nano-amygdalin—a nanoformulated compound derived from apricot seed meal—against the green peach aphid Myzus persicae, along with its impact on tomato (Solanum lycopersicum) plant defense responses. Amygdalin was extracted from apricot seed meal and immobilized onto silica nanoparticles synthesized from rice straw. The immobilization process achieved an efficiency of 92.4 % after 6 h. Transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FTIR) confirmed the successful formation and structural characteristics of the nano-amygdalin complex. Laboratory bioassays demonstrated that nano-amygdalin significantly reduced aphid survival and fecundity, with the highest tested concentration (0.5 mg/mL) decreasing survival to 12 % and fecundity to 0.65 nymphs/female/day. Furthermore, tomato plants treated with nano-amygdalin under aphid infestation showed enhanced growth and attenuated oxidative stress, evidenced by reduced hydrogen peroxide and malondialdehyde levels. Activities of defense-related enzymes, including peroxidase and polyphenol oxidase, were significantly elevated in treated plants. Notably, treated plants also exhibited increased levels of cell wall-bound phenolics and peroxidase, suggesting enhanced lignification as part of the induced defense mechanism. These findings highlight the potential of nano-amygdalin as a sustainable, plant-compatible biopesticide that not only suppresses aphid populations but also fortifies host plant defense pathways.