Tea (Camellia sinensis), is a major contributor to the nation's economic output. However, its production is decreased by fungal diseases like tea root rot (Fusarium oxysporum). Hence, this study was initiated to evaluate the efficacy of fungal bio-agents against the disease. Samples were taken from Gumero and Wish-wash tea plantation areas in southwest Ethiopia. Using the dual culture method five fungal bioagents namely, Tg01, Tg02, Tg03, Tg04, Tg05, and Trichoderma harzianum, Trichoderma asperellum, and Trichoderma viride were characterized and evaluated. The results revealed significant differences (P < 0.01) between the isolates. The range of radial growth was 1.76 to 4.41 mm/day. The lowest (1.76) and the highest (4.41) mm/day radial growth were recorded from Tg01 and T. asperellum respectively. Likewise, Tg01 and T. asperellum revealed the lowest (43.1%) and highest (92.9%) inhibitory percentages. The Trichoderma species exhibited the highest degree of inhibition against the target pathogen and the fastest radial growth when compared to the other isolates. The next stage of the study should be to choose and identify the best possible bio-control agents, followed by field and greenhouse evaluation. Overall, the investigated isolates demonstrated positive and promising outcomes under in vitro evaluation of the target pathogen in this study.

Keywords: Antagonist; Biocontrol; Fungal species; Fusarium oxysporum; Trichoderma spp.