Biofabrication of iron oxide nanoparticles from green seaweed Ulva lactuca and screening for its insecticidal activity

The primary aim of the research was to utilize Ulva lactuca, green seaweed, to biofabricate iron oxide nanoparticles (FeNP) and evaluate their insecticidal efficacy against Tuta absoluta, a pest that primarily impact tomato commercial crop. For the purpose of characterising biosynthesized nanoparticles, tools such as UV-Vis spectroscopy, FT-IR, XRD, SEM, and TEM were used. Inferred from the results is that, the aggregation of iron oxide nanoparticles is confirmed by the colour change from yellow to dark brown. Additionally, spectra from the 200–1000 range are absorbed by UV–Vis spectroscopy. The FT-IR peaks correspond to the band at 778 cm in the Ulva lactuca extract and correspond to F-O stretches of Fe2O3, confirming the production of nanoparticles. The band at 2851 cm may be due to C-N stretching from unreacted impurities or CO2 in the sample compartment. According to a TEM image of iron nanoparticles, the majority of these particles are almost spherical in shape, and their average size was found to be between 50 and 250 nm. Pure iron oxide nanoparticles were recovered from Ulva lactuca by green synthesis. The prominent peaks in the range of 30 to 70θ indicated by XRD demonstrate the extraction of pure iron oxide nanoparticles from Ulva lactuca. The results of the insecticidal tests indicate that the synthesised iron oxide nanoparticles had a satisfactory death rate of 63% with an observed concentration of 77.32 ppm. The values for the LC50 are 97.25 and LC90 are 110.8 ppm. The values were compared one to the other with the control. The insect Tuta absoluta will be a possible target for control with iron oxide nanoparticles generated from Ulva lactuca.