Efficacy of Synthesized Nanoparticles from Pseudomonas fluorescens on the Mycelial Growth Suppression of Ustilaginoidea virens Causing False Smut of Rice

Abstract

Rice is one of the most important food grain crops grown throughout the world as well in India. The present study aimed to evaluate the antifungal efficacy of different synthetic nanoparticles derived from Pseudomonas fluorescens and standard fungicide (copper oxychloride @ 2500ppm) on the radial mycelial growth of Ustilaginoidea virens, the causal agent of false smut disease in rice, under in vitro conditions. Fourteen treatments, including control (T14) and standard fungicide (T13), were assessed at 5th, 7th, and 10th days of incubation. The findings showed notable variations between treatments in suppressing the mycelial growth of U. virens of the formulations tested, treatment T3 showed the least mycelial growth (6.32 mm, 13.35 mm, and 18.57 mm on days 5, 7, and 10, respectively) and had the highest percentage of inhibition (54.97%) compared to the control, with T7 (53.37%) and T2 (51.96%) closely following. The fungicide at 2500 ppm achieved 47.74% inhibition, outperforming SiO2NPs but remaining less effective than Ag NPs and ZnO NPs. In comparison, the control treatment (T14) exhibited the highest mycelial growth (22.57 mm, 31.50 mm, and 41.24 mm) with no restrictions. These results indicate that synthesized nanoparticles from Pseudomonas fluorescens have significant antifungal activity against U. virens and may act as effective eco-friendly substitutes for chemical fungicides in controlling false smut disease in rice.