Myco-synthesized nanoparticles as a promising bioinsecticide tool to control mosquito vectors

The present study determined the larvicidal efficacy of mycosynthesized silver nanoparticles of three different entomopathogenic fungus (EPF) against the fourth instar larvae of Aedes and Culex. These mycosynthesized silver nanoparticles have been characterized by FTIR, SEM and UV-vis analysis. The results obtained ascertain the effectiveness of EPF against the larvae of both mosquitoes respectively. Treatments of different concentrations of EPF, Metarhizium, Trichoderma and Fusarium, based silver nanoparticles have shown promising results. Larvae of genus Aedes and Culex showed gradual increase in mortality with the increasing concentrations of EPF's conidal suspension and their mycosynthesized silver nanoparticles. In larvicidal bioassays, some concentrations of mycosynthesized silver nanoparticles showed complete mortality and there were no pupal and adult emergence. The control in which larvae were exposed to distilled water did not show any mortality after 24hrs. Within 24 to 72hrs, larvae completed their metamorphosis and developed into pupae prior to adult. The entomopathogenic fungi and mycosynthesized silver nanoparticles showed various degrees of larvicidal efficacy against mosquitoes of genus Aedes and Culex. Furthermore, some behavioral changes were observed in exposed larvae of Aedes and Culex respectively. After 2-3 hours post exposure some larvae became hyperactive and showed erratic swimming and loss of balance. Moribund or dead larvae were found after 5 -10 hours. At the end of 24hrs, almost all larvae were subsequently died with increasing concentrations of entomopathogenic fungi and mycosynthesized silver nanoparticles.