Biological Synthesis of Mancozeb and Hexaconazole Conjugated Silver Nanoparticles From Goat Urine and Their Antifungal Efficacy Against Colletotrichum Gloeosporioides

The present study reports the eco-friendly synthesis of silver nanoparticles (AgNPs) using goat urine as a natural reducing and stabilizing agent, followed by their conjugation with the fungicides Mancozeb and Hexaconazole. The synthesized nanoparticles were characterized using UV–Visible spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FTIR). UV–Vis analysis confirmed the formation of AgNPs with a surface plasmon resonance peak at 390 nm, while Mancozeb- and Hexaconazole-conjugated AgNPs (Mc-AgNPs and Hc-AgNPs) exhibited red-shifted peaks at 403 nm and 432 nm, respectively, indicating successful conjugation. SEM analysis revealed spherical nanoparticles with sizes ranging between 20–32 nm, while XRD confirmed their crystalline nature with characteristic fcc peaks. FTIR spectra demonstrated the involvement of goat urine biomolecules in nanoparticle stabilization and verified fungicide binding through distinctive functional groups. The antifungal efficacy of AgNPs, fungicides, and their conjugated forms was evaluated against Colletotrichum gloeosporioides. AgNPs exhibited moderate inhibition, whereas fungicide-conjugated AgNPs demonstrated significantly enhanced activity. Mc-AgNPs produced the largest inhibition zone (4.1 cm), representing a ~115.78% improvement over Mancozeb alone and a 41.37% higher efficacy compared to Hc-AgNPs. These results highlight the synergistic effect of fungicide conjugation, likely due to improved nanoparticle penetration and enhanced fungicide delivery. This study demonstrates that goat urine-mediated green synthesis of fungicide-conjugated AgNPs offers a sustainable and effective approach to plant disease management. Such nanoconjugates may reduce fungicide dosage, mitigate environmental toxicity, and delay resistance development, providing a promising alternative in sustainable agriculture.