Abstract
In this study, two marine algae, Avrainvillea amadelpha and Codium edule, and their synthesized silver nanoparticles were evaluated against the second larval instars of the housefly Musca domestica. The marine algae-fabricated silver nanoparticles (AgNPs) were examined by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction analysis (XRD). The precolored aqueous silver solution changed from pale yellow to brown by mixing the algae extracts, revealing Ag nanocomposite production. There was a maximum UV-vis absorption at 400 nm for A. amadelpha and 420 nm for C. edule. SEM results showed that the A. amadelpha- and C. edule-fabricated AgNPs were spherical and irregular in shape. A. amadelpha extract alone gave higher effective mortalities against M. domestica larvae, which were 22.1-98.3% in the tested concentrations (62.5-1,000 ppm), while a highly significant increased mortality (36.9-99.7%) was obtained from concentrations ranging from 6.3-100 ppm when A. amadelpha extract was mixed with silver nanoparticles. C. edule extract alone gave moderate effective control with 15.9-90.3% mortality using the above concentrations, whereas the mortality significantly increased (21.8-95.8%) with concentrations ranging from 6.3-100 ppm when C. edule extract was mixed with silver nanoparticles. According to the LC50 values, A. amadelpha with silver nanoparticles (LC50 9.66 ppm) provided more effective control against larval stages of M. domestica than A. amadelpha alone (LC50 133.08 ppm) by a factor of 13.776. Additionally, C. edule alone provided moderately effective control (LC50 300.37 ppm), while when mixed with silver nanoparticles, it provided highly effective control (LC50 21.34 ppm) by a factor of 14.075. Some algae extracts that synthesize silver nanoparticles offer a promising role in housefly integrated pest management (IPM) and may be an effective alternative to conventional synthetic insecticides.