Chemical Synthesis of Copper Nanoparticle and its in-vitro Efficacy Against Phytophthora nicotianae

Various Phytophthora species have long been associated with different citrus diseases, including gummosis, root rot, fruit brown rot, and citrus decline worldwide, including in India. Among these, Phytophthora nicotianae has gained considerable attention due to its significant role in causing citrus gummosis, a major factor contributing to yield losses. Studies have shown that P. nicotianae can lead to approximately 10–30% yield reduction due to gummosis. Considering this impact, the present study aims to synthesize the copper nanoparticles and evaluate its antifungal efficacy against P. nicotianae. Due to their large specific surface area and inexpensive cost, copper nanoparticles have garnered a lot of interest. Herein, by using a new, simple method, copper nanoparticles (Cu NPs) have been successfully created. The technique relies on the chemical reduction of aqueous copper salt at low temperatures (80°C) with ascorbic acid acting as a reducing agent. The greatest absorbance at 340 nm in the UV-Vis spectroscopic analysis of synthesized CuNPs indicated the existence of CuNPs in the reaction mixture. According to in-vitro effectiveness experiments, 50 ppm and 100 ppm concentration of CuNPs significantly inhibited mycelial growth of P. nicotianae by up to 59.25% and 100%, respectively. Overall, the present study emphasizes the benefits of synthesized CuNPs on P. nicotianaeas a nano-fungicide at very low concentration as compared to recommended chemical fungicides, additionally, a safe substitute for synthetic chemical fungicides to prevent harmful environmental effects.