Exploring the integrated strategies for enhanced stem rot disease management in groundnut

Groundnut (Arachis hypogaea L.), a significant edible oilseed crop, suffers yield reductions due to stem rot incited by Sclerotium rolfsii Sacc. A 2022 survey across three major groundnut-growing districts of Tamil Nadu revealed stem rot incidences ranging from 16.57 % to 39.55 %, with the highest occurrence recorded in the Kalpadai region of Kallakurichi. A total of 10 S. rolfsii isolates were obtained and pathogenicity assays identified the Sr3 isolate as the most virulent, causing 44.85 % disease incidence. Morphological and molecular characterization, including ITS-based analysis, confirmed the pathogen as S. rolfsii (OQ5681821). Principal Component Analysis (PCA) demonstrated that pathogenic variability negatively impacted yield traits such as seed length, plant height and shelling percentage. Native biocontrol agents Trichoderma asperellum Tr4 (OQ581458) and Bacillus licheniformis B5 (OQ195791) exhibited significant antagonistic effects, inhibiting S. rolfsii mycelial growth by 88.88 % and 70.55 % respectively. Additionally, vermicompost and neem cake extract (20 % concentration) suppressed pathogen growth by 88.22 % and 78.01 % respectively, using the poisoned food technique. Compatibility studies confirmed that T. asperellum Tr4 and B. licheniformis B5 were mutually compatible as well as with vermicompost and neem cake. Combined treatments of bioagents with vermicompost and neem cake in pot and field trials effectively reduced stem rot incidence and improved yield parameters in groundnut. This study offers valuable insights into S. rolfsii pathogenesis and highlights sustainable, eco-friendly strategy for managing stem rot, thereby enhancing groundnut productivity.