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

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 (TiO 2 ) 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 TiO 2 –Ag nanosuspension on the growth of P. palmivora under exposure to UV, Visible and without irradiation. The sol–gel process was used to synthesize TiO 2 , and ultrasonics was used to integrate silver nanoparticles into TiO 2 . 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 TiO 2 -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 TiO 2 –Ag was 92.4 nm. The disc diffusion method was used to test the antifungal inhibitory of 0.1%, 0.3%, and 0.5% TiO 2 –Ag against P. palmivora . The antifungal activity of the TiO 2 –Ag showed strong resistance under exposure to visible light, and the optimum concentration of TiO 2 –Ag was 0.5%.