Evaluation of Larvicidal Efficacy of (Castor) Plant Extract and Synthesized Green Silver Nanoparticles against .

Background: mosquitoes are the most important group of vectors having ability of transmitting pathogens including arboviruses that can cause serious diseases like Chikungunya fever, Dengue fever and Zika virus in human. Biosynthesis and the use of green silver nanoparticles (AgNPs) is an important step in the search of reliable and ecofriendly control of these vectors.

Methods: In this study an aqueous leaves extract of (castor) and silver nanoparticles (AgNPs) synthesized from this extract were evaluated as larvicidal agent for 2 and 3 instar larvae of the . Different concentrations (50, 100, 150, 200 and 250ppm) of plant extract and synthesized nanoparticles were prepared and applied on second and third instar larvae. The percent mortality was noted after 6, 12, 18, 24, 30, 36, 42 and 48H of exposure and subjected to probit analysis to calculate LC and LC.

Results: Synthesized Ag nanoparticles were characterized by UV-Vis spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and energy-dispersive X-ray spectroscopy (XRD). The nanoparticles were more toxic against larvae of with LC value (49.43ppm) and LC value (93.65ppm) for 2 instar larvae and LC (84.98ppm) and LC (163.89ppm) for 3 instar larvae as compared to the plant extract (149.58ppm, 268.93ppm) and (155.58ppm, 279.93ppm) for 2 and 3 instar larvae of respectively after 48H.

Conclusion: Our results suggest the extract of and synthesized nanoparticles as excellent replacement of chemical pesticides to control the vector mosquitoes.