Efficacy of green synthesized silver nanoparticles against Tetranychus urticae Koch (Acari: Tetranychidae)

Biosynthesis of metallic nanoparticles is a novel area of research which have cost-effective and bio rational advantages over traditional physio-chemical methods. Tetranychus urticae Koch (Acari: Tetranychidae) is a major pest of many agricultural crops and ornamental plants. Silver nanoparticles (AgNps) are considered as important tool for sustainable insect pest management program. Present study was performed to evaluate the toxic effects of silver nanoparticles synthesized by cinnamon bark against Tetranychus urticae. The characterization of prepared nanoparticles was carried out by ultraviolet spectroscopy and X-ray diffraction. Five different concentrations of silver nanoparticles (12.00, 6.00, 3.00, 1.5 and 0.75 g/L) along with control (distilled water) were tested for their toxicity against Tetranychus urticae adults. The results indicated an increasing trend of mortality percentage along with the increasing concentrations of silver nanoparticles. Silver nanoparticles were significantly effective against Tetranychus urticae. The highest mortality 64.93 % was observed for 12 g/L concentrations of silver nanoparticles at 120 hours' time intervals whereas; lowest mortality 10.56 % was noted for 0.75 g/L after time interval of 24 hours. The least LC50 (3.38) and LT50 (58.70) value was demonstrated at time interval of 120 hrs and concentration of 12 g/L respectively against T. urticae. This study proved that application of silver nanoparticles at high concentrations could be effective for control of Tetranychus urticae population associated with agricultural crops and ornamental plants with low toxicity effects on non-target organisms.