While the mold that is blue-green Penicillium italicum is one of the most serious post-harvest plant infections, compromising the integrity of citrus and many other crops during storage and transportation, there is as yet no sensor for its detection on-site, or in the eld. For the rst time, we present the development of a novel CaMn 4 O 8 -G-SiO 2 (CaMnGS) sensor to detect the presence of Penicillium italicum mold. CaMnGS was synthesized using a self-assembly technique in this study. CaMnGS sample demonstrated outstanding stability, high selectivity, and notable characteristics for Penicillium italicum fungus detection. For Penicillium italicum fungus sensing, the CaMnGS displayed a large linear range of (50-100) μL, and a low detection limit of 0.50 μL. Signi cantly, the CaMnGS sensor was capable of swiftly detecting the Penicillium italicum fungus in wastewater. The CaMnGS generated had no effect on cell survival and had tremendous potential for Penicillium italicum fungal sensing. The mesoporous CaMnGS sensor may also detect the presence or absence of the fungus Penicillium italicum. This method might be used to identify the fungus Penicillium italicum. This is also the rst attempt to discuss the fabrication of an electrochemical sensor employing a mesoporous CaMnGS nanoparticle composite as a platform for the selective detection of Penicillium italicum.