Evaluation of the Inhibitory Evaluation of the Inhibitory Efficacy of a Green-synthesized ZnO Nanoparticle Prepared Using Beta vulgaris L. against Some Root Rot Fungi in the Orchards of Karbala Governorate

Abstract

Root rot diseases are significant problems affecting many plants due to infection by various pathogenic fungi, necessitating the search for effective and environmentally safe control methods, such as the use of green-synthesized zinc oxide nanoparticles (ZnO-NPs). The aim of this study is to evaluate the effectiveness of green-synthesized zinc oxide nanoparticles in inhibiting fungi that cause root rot in certain agricultural plants. Beta vulgaris L. has been used for this purpose, as it is rich in compounds with antimicrobial properties. The plant has attracted increasing consideration for its possible role in combating many plant pathogens, particularly rot diseases, which are among the most significant factors affecting many plant hosts, including C. roseus, S. lycopersicum and G. hirsutum, and pose a major threat to these plants. Samples were collected from the roots of certain plants that have root rot (S. lycopersicum, C. roseus, G. hirsutum) from different orchards in Karbala Governorate. Morphological and microscopic traits were used to identify the isolated fungi. The following species were presumptively identified: Alternaria alternata, Rhizoctonia solani, Fusarium solani. They were treated with nano-zinc oxide prepared from the water-based extract of the B. vulgaris L. and zinc acetate, followed by heating and stirring, then drying and calcination. Subsequently, various concentrations of ZnO nanoparticles were added to the PDA medium containing the fungi; the plates were incubated, and fungal growth was measured to determine the inhibition rate. The findings demonstrated a clear correlation between the extract’s Zno concentration and its ability to suppress the fungus that was isolated from the diseased plants’ roots. The concentration of 200 ppm recorded the highest rate of inhibition diameter compared to the other concentrations used. The inhibition rates were 85.56%, 83.33%, and 80.00% for A. alternata, F. solani, and R. solani, respectively, with a clear difference in the degree of response between the fungal species. Zinc oxide nanoparticles made from B. vulgaris L. aqueous extract exhibited inhibitory activity against the isolated fungi, confirming their antifungal efficacy