Silver nanoparticles (Ag NPs) was achieved by using leaf extract of Borago officinalis plant as eco-friendly reducing and capping
agent. The results obtained from ultraviolet-visible spectrophotometer, dynamic light scattering, scanning & transmission electron
microscopy, energy dispersive X-ray, and fourier transformed infrared confirmed the biosynthesis and the physical characterization
of the produced nanoparticles. The synthesized Ag NPs was greatly more toxic to Spodoptera littoralis compared to
crude extract. The LC50 values of the crude extract, and synthesized Ag NPs were 22.6 and 0.33 mg/g while LC90 values were
969.0 and 1.7 mg/g, respectively. Ag NPs and plant extract caused a significant elongation in larval period (18.02 and 18.82
days), respectively) compared with (15.78 days) in the control treatment. Whereas, there was no significant elongation in the
pupal period in both males and females in case of Ag NPs and plant extract compared to the control treatment. Our results
declared that the leaf crude extracts of B. officinalis and green synthesis of silver nanoparticles using it have the potential to be
used as an ideal eco-friendly approach for controlling S. littoralis. This is the first report on the pesticide activity of this plant
extract and its synthesized silver nanoparticles to control this insect pest.