Green synthesis of nanoparticles using plant-based extracts is momentously used in different fields of science because of their environment-friendly nature and cost-effectiveness. In the present study, silver nanoparticles were synthesized by using rice husk (non-toxic agricultural by-product) to determine their efficacy against aphid's (Sitobion avanae) mortality and antioxidant enzymes. UV-VIS spectroscopy of synthesized nanoparticles showed the maximum absorption peak at 440nm, FTIR exhibited different peaks, and SEM confirmed the roughly spherical shape and 70-80nm size of silver nanoparticles. Aphids were reared on wheat seedlings in the laboratory at 20-25°C and 16:8 (light:dark) photoperiod. Insecticidal bioassays were conducted on aphids at three different concentrations (200ppm, 400ppm, 600ppm) of nanoparticles for 2days. Results showed the highest mortality of aphids being 93.3% at 600ppm nanoparticle concentration after 2days while the lowest mortality was observed at 200ppm. Furthermore, the effect of silver nanoparticles on antioxidant enzymes was studied. Results of enzyme assays revealed that enzyme activities of catalase and glutathione-s-transferase increased in response to increased nanoparticle concentration. The current findings suggested that silver nanoparticles have probation for replacing commercially available insecticides for combating pests.