A growing concern has emerged regarding the extensive use of pesticides. This study aimed to explore an eco-friendly alternative by utilizing silver nanoparticles (AgNPs) derived from Rosmarinus officinalis L. leaves, which were evaluated against Earias insulana and Pectinophora gossypiella UV-VIS spectroscopy analysis of the Rosemary-AgNPs exhibited an absorption at wavelength around 403 nm, characteristic of silver, confirming successful nanoparticle synthesis. HPLC analysis identified twenty-six compounds from R. officinalis, contributing to its chemical composition. Additionally, TEM imaging revealed the spherical morphology of the AgNPs with an average diameter of 20-22 nm. The LC₅₀ values for P. gossypiella and E. insulana were determined to be 18.655% and 16.75%, respectively, indicating the potency of the AgNPs against these pests. Furthermore, the significant prolongation in the developmental stages of both insects, with total immature stages taking 33.83 and 34.9 days for P. gossypiella and E. insulana, respectively compared to the untreated group 21.9 and 24.3 days. Biochemical analysis demonstrated a marked decrease in total protein and carbohydrate levels, reducing to 48.5 and 11.5 mg glucose/g, opposed to 114.0 and 29.5 in the untreated, respectively. Conversely, a notable increase in total lipid content, reaching 12.0 mg/g in the P. gossypiella strain, compared to 7.5 in the untreated group. However, in E. insulana, there was a substantial reduction to 2.3 mg/g, down from 4.1 mg/g in the untreated group. Additionally, the cuticle and midgut levels, the treatments led to histological irregularities in both tested insects when compared to the untreated controls. The findings emphasize the viability of eco-friendly alternatives, promoting further exploration and utilization of nature-derived solutions in pest control over conventional chemical insecticides.