Sustainable control of Fusarium oxysporum in cumin (Cuminum cyminum L.) through intervention of botanicals, antagonistic fungi, and soil solarization

Abstract

Fusarium wilt, caused by Fusarium oxysporum f. sp. cumini, is one of the most devastating diseases constraining cumin (Cuminum cyminum L.) production worldwide. A field experiment was conducted to evaluate the efficacy of an integrated disease management (IDM) strategy comprising soil solarization, neem cake, and Trichoderma viride for suppressing Fusarium wilt and improving crop productivity. Pooled analysis revealed that all integrated treatments significantly reduced disease incidence and soil pathogen population while enhancing seed yield compared with the untreated control. Among the treatments, 20 days of soil solarization combined with neem cake (0.5 t ha⁻¹) and seed treatment with T. viride (8 g kg⁻¹ seed) proved to be the most effective, recording the lowest Percent Disease Index (PDI; 5.31), the highest disease reduction (89.7%), the greatest decline in pathogen population (81.7%), and the maximum seed yield (173 g plot⁻¹). This treatment was closely followed by 30 days of soil solarization combined with neem cake and T. viride, which achieved a PDI of 5.69, disease reduction of 88.7%, and pathogen population reduction of 78.9%. In contrast, the untreated control exhibited the highest disease severity (PDI 58.81) and the lowest seed yield (60 g plot⁻¹). Soil solarization increased soil temperature to 56.86°C at a depth of 15 cm, creating unfavorable conditions for pathogen survival and enhancing the efficacy of neem cake and T. viride. The synergistic integration of physical, organic, and biological approaches effectively reduced soil inoculum, suppressed Fusarium wilt, and substantially improved cumin productivity. These findings demonstrate that integrating soil solarization with neem cake and T. viride provides an environmentally sustainable and highly effective