Effectiveness of bacterial inoculant and ginger extract in suppressing Alternaria solani causing early blight in tomato

Abstract

Early blight (EB) , caused by the fungus Alternaria solani, represents a serious problem in tomato production. This study aimed to evaluate the effectiveness of a synergistic strategy, combining phosphorus-solubilising bacteria PSB31 with ginger extract (GPE) in inhibiting early blight. The findings showed that strain PSB31 (identified as Bacillus sp. IMAU61039) presented the highest level of inhibition (46.9%) against the mycelial growth of A. solani, the causal agent of early blight in tomato plants. Among the treatments, the combination of PSB31 and GPE exhibited the most significant inhibitory effect on the mycelial growth (65.4%) of A. solani compared to the control. Moreover, under greenhouse conditions, tomato seeds treated with this combination showed the highest rate of
early-blight inhibition (77.81%) compared to the untreated control (72.71%) and chemical disease control (90.23%). Notably, treatment of tomato seeds with the combination of PSB31 and GPE promoted seed germination (93.54%) and seedling development under A. solani infection. These results indicate the potential application of strain PSB31 in combination with GPE for controlling diseases caused by A. solani in tomato plants.