Green Pesticide High Activity Based on TiO₂ Nanosuspension Incorporated Silver Microspheres Against Phytophthora...

Cocoa pod production has experienced a significant decline due to attacks by the Phytophthora palmivora (P. palmivora) fungus, which is the main cause of cocoa pod rot. To overcome this problem, Titanium dioxide (TiO₂) was chosen because of its potential as an antifungal, and its activity can be increased by adding silver nanoparticles (AgNPs). This research aims to determine the antifungal properties of TiO₂-Ag nanosuspension on the growth of P. palmivora under exposure to UV, Visible and without irradiation. The sol-gel process was used to synthesize TiO₂, and ultrasonics was used to integrate silver nanoparticles into TiO₂. Characterization of UV-Vis diffuse reflectance spectroscopy (UV-DRS) shows a change in the energy gap from 3.24 to 2.82 eV. The Fourier confirmed the crystal structure of the TiO₂-Ag anatase transform infrared spectroscopy (FTIR) spectrum, which showed the stretching vibration peak of the Ti-O and Ag-O bonds (463.88 cm^-1). Particle size analysis (PSA) characterization revealed that the nanoscale of TiO₂-Ag was 92.4 nm. The disc diffusion method was used to test the antifungal inhibitory of 0.1%, 0.3%, and 0.5% TiO₂-Ag against P. palmivora. The antifungal activity of the TiO₂-Ag showed strong resistance under exposure to visible light, and the optimum concentration of TiO₂-Ag was 0.5%.