Potantial of Bioagents for Sustainable Management of Sclerotium Rot of French Bean

Sclerotium rot caused by Sclerotium rolfsii is a destructive soil-borne disease which severely limits French bean productivity, highlighting the need for ecologically safe and sustainable disease management solutions. This study evaluated five bioagents: Trichoderma harzianum, T. asperellum, Bacillus subtilis, Pseudomonas fluorescens, and a microbial consortium (Biomix) under pot culture conditions using the sick soil technique. Captan 50% WP served as the standard check. All bioagents significantly improved seed germination (51.67-83.33%) compared with the untreated control (41.67%). T. harzianum recorded the highest germination (83.33%), surpassing Captan 50% WP (61.67%). Pre-emergence seed rot (PRESR) was markedly reduced in all treatments (16.67-48.33%) compared to the control (58.33%), with T. harzianum exhibiting the lowest PRESR (16.67%), followed by B. subtilis (25.00%). Captan recorded 38.33% PRESR. Post-emergence seedling mortality (POESM) ranged from 13.33% to 33.33% among bioagents, against 40.00% in the control. T. harzianum again showed the least POESM (13.33%), followed by B. subtilis (18.33%). Captan recorded 28.33% POESM. Overall mean mortality was lowest with T. harzianum (15.00%), while Captan (33.33%) performed better than T. asperellum and Biomix. The study demonstrates that T. harzianum and B. subtilis offer effective, eco-friendly suppression of Sclerotium rot, underscoring their potential as sustainable agroecological alternatives to chemical fungicides in French bean cultivation.