Biological management of cumin Fusarium wilt caused by Fusarium oxysporum f.sp. cumini using antagonistic rhizospheric bacteria Bacillus licheniformis

Abstract: The field survey conducted in Rajasthan, India, unveiled the widespread occurrence of Fusarium wilt in cumin fields that have been continuously cultivated for approximately 4 to 5 years. The incidence of this disease exceeded 30%, affecting cumin plants at all stages of growth, with severe symptoms ultimately resulting in the complete mortality of the plants. In laboratory studies, a bacterial isolate known as Bacillus licheniformis (CSR-D4) exhibited remarkable in vitro effectiveness, significantly inhibiting Fusarium oxysporum f.sp. cumnini (FOC) mycelial growth by an impressive 79.85%. In controlled pot experiments, cumin plants treated with B. licheniformis (CSR-D4) displayed milder symptoms than untreated plants, demonstrating a notably higher tolerance level, with only a 15% disease incidence as opposed to 90% in untreated plants. Further analysis of defense enzymes revealed elevated chlorophyll, carotenoid, peroxidase activity levels, and proline content in cumin plants treated with B. licheniformis (CSR-D4). Field assessments confirmed the efficacy of this bacterial isolate, as it successfully suppressed wilt incidence by 60%, significantly increased crop yield by 71.16%, and promoted root and shoot growth. Notably, applying B. licheniformis (CSR-D4) did not negatively impact beneficial microorganisms, and no adverse phytotoxic symptoms were observed. This study underscores the considerable potential of B. licheniformis (CSR-D4) in managing Fusarium wilt, offering an environmentally friendly and highly effective solution to enhance the health and productivity of pea plants.