ANTIFUNGAL ACTIVITY OF Enhydra fluctuans L. EXTRACT AGAINST Fusarium incarnatum CAUSING POSTHARVEST FRUIT ROT OF DRAGON FRUIT

Abstract

This study was conducted to isolate and identify the fungal pathogen causing disease and to evaluate the antifungal activity of the Enhydra fluctuans L. extract against Fusarium, the causal agent of postharvest fruit rot in dragon fruit. Isolation from diseased dragon fruit samples revealed that strain TL1 exhibited morphological characteristics typical of the genus Fusarium. Sequence analysis of the internal transcribed spacer (ITS) region showed that strain TL1 shared 100% sequence similarity with published F. incarnatum sequences in the GenBank database. In addition, Enhydra fluctuans L. extract exhibited inhibitory effects on the growth of F. incarnatum under in vitro conditions. Complete inhibition of mycelial growth was observed at a concentration of 700 µg/mL, whereas spore germination was completely suppressed at 5,000 mg/mL. Antifungal activity increased in a concentration-dependent manner, as evidenced by a significant reduction in colony diameter and spore density on PDA medium. These findings indicate that Enhydra fluctuans L. extract has potential for application as a plant-derived, environmentally friendly, and safe natural antifungal agent for postharvest preservation of dragon fruit, contributing to a reduced reliance on synthetic chemical fungicides.