The fungal species isolated from infected seedlings showed the appearance of root rot fungi, including Rhizoctonia solani, Fusarium solani, and Macrophomina phaseolina. The evaluation of two biological control agents, Trichoderma viride and Trichoderma harzianum, showed their ability to inhibit pathogenic fungi, and as per Bell’s scale, the inhibition percentage ranged from 1% to 2%. Both biological controls, T. harzianum and T. viride, significantly reduced the incidence of infection caused by the fungi. T. harzianum reduced the incidence of R. solani (20%), which was at par with T. viride (33.33%) reduction of R. solani, and a reduction in M. phaseolina and F. solani with T. viride amounted to 30.00% and 33.33%, respectively, compared with the control treatment inoculated with the fungus only (80.00%). Results also revealed that these two types lessened infection severity, where the highest decrease in infection severity with F. solani was 0.30 and 0.20 for T. viride and T. harzianum, respectively. In addition, both biological controls also positively affected the plant growth characteristics. T. harzianum with M. phaseolina increased shoot height (22.20 cm) compared with the pathogenic fungus treatment (16.46 cm), respectively. Moreover, the T. harzianum with M. phaseolina treatment significantly raised root length and dry weight compared with the control treatment.
Cowpea (Vigna sinensis L.), F. solani, M. phaseolina, R. solani, T. viride, T. harzianum
In cowpea (Vigna sinensis L.), the root rot infection caused by fungi, including Rhizoctonia solani, Fusarium solani, and Macrophomina phaseolina, gained significant reduction and control by bioagents fungi (Trichoderma viride and Trichoderma harzainum).