Harnessing the biocontrol and phytostimulatory potential of endophytic fungi against damping -off disease in okra

Abstract Okra ( Abelmoschus esculentus L. Moench) is an economically important vegetable crop, with summer cultivation critical for early market supply. Seedling damping-off, primarily caused by Rhizoctonia solani , poses a major constraint, often leading to severe yield losses. This study evaluated the potential of fungal endophytes for managing damping-off under summer cultivation in Himachal Pradesh, India. Field surveys (2023–2024) across Kangra, Mandi, and Hamirpur districts recorded disease incidence of 31.7–84.3%. Among 44 isolates recovered, R. solani JPO1 was identified as the predominant pathogen via morpho-molecular characterization. Forty-two fungal endophytes were screened for antagonism and plant growth-promoting (PGP) traits; eight isolates with strong activity were further characterized: Coniothyrium sp. E1P, Xylaria juruensis E4P, Aspergillus terreus E10P, Epicoccum sp. E13P, Aspergillus welwitschiae E16P, Fusarium proliferatum E25P, F. solani E26P, and Epicoccum sp. JPE2. Glasshouse and field evaluations identified F. proliferatum E25P as the most effective isolate, significantly enhancing plant growth and suppressing damping-off. Root colonization, confirmed by plate counts and confocal laser scanning microscopy, demonstrated robust endophytic establishment in treated plants. These results highlight the potential of fungal endophytes as sustainable, eco-friendly alternatives to chemical fungicides for effective damping-off management in okra.