Investigating the activity of Bacillus subtilis and Trichoderma harzianum to mitigate Fusarium wilt disease of diverse cultivars of Vicia faba

Fusarium wilt causes destructive effects on Vicia faba (VF). This study is innovative because it evaluates the comparative effects of various biological treatments on different VF cultivars to determine the therapeutic potential of each treatment against Fusarium wilt. In this study, the suppression of F. verticillioides (FV) by Bacillus subtilis and Trichoderma harzianum was compared at both the pot level and in vitro. The findings indicated that both B. subtilis and T. harzianum have antifungal effects on F. verticillioides in vitro, exhibiting mycelium inhibition percentages of 45.88% and 68.20%. Our results showed that treatments with T. harzianum significantly reduced the disease incidence (DI) in both the V. faba 'Giza-716' (G) and 'Sakha-101' (S) cultivars, providing comparable protection at 70.58% and 72.22%, respectively. After the afflicted plant received biological therapies, a notable increase in all yield components was observed. The G and S cultivars treated with T. harzianum exhibited the highest PPO activity, measuring 116.70% and 227.70%. The S cultivar treated with T. harzianum showed the highest POD activity at 289.60%. In conclusion, T. harzianum and B. subtilis as potential bio pesticides exhibited high efficacy against F. verticillioides, which causes wilt in several Vicia faba cultivars, due to their effectiveness and environmental friendliness.