author(s)
S Gogate, S Rahman and P Dutta

abstract
The rice moth, Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae), is an important stored-product pest all over the world. Biosynthesis of pesticides from plant extract is most promising new approach for pest control. The present study was carried out for two years 2015-16 and 2016-17 to ascertain the larvicidal activity of synthesized silver nanoparticles (AgNP’s) using plant leaf extracts from Ocimum sanctum (L.). Synthesis was confirmed through UV-Vis spectrophotometer in wavelength range of 200-700 nm. The peak was recorded at 422 nm which confirmed the formation of silver nanoparticles, zeta potential values were found to be -16.4 mV, FT-IR analysis showed strong peaks at ranges of 800-4000cm^-1 which exhibited presence of different types of functional groups viz., (O-H, H-H, C-H, C-C and N-H). TEM analysis determined the size and shape of Ocimum sanctum (L.) AgNP’s with average size of 64.04 nm which is roughly circular or spherical in shape. Efficacy of green synthesized silver nanoparticles (AgNP’s) from Ocimum sanctum (L.) against Corcyra cephalonica (S.) was evaluated in dilutions range 200, 300, 400 and 500 ppm. Larval mortality of C. cephalonica was found to be (80% and 83.33%) both the years 2015-16 and 2016-17. The LC₅₀ was also calculated both in 2015-16 and 2016-17; the lowest LC₅₀ value was recorded to be 244.04 ppm after fifth day of the treatment. As the nanoparticles concentration and days after treatment increased, larval mortality also increased. There were statistically significant differences in larval mortality between concentrations. The result suggested that the use of plants for synthesis of silver nanoparticles may be considered as environmentally safer and greener approach for pest control.