Evaluation of Fungal Bio-Agents Against Tea Root Rot (Fusarium oxysporum) in South-Western Ethiopia

Background and Objective: The most often consumed stimulant plant, tea (Camellia sinensis), is a major contributor to the nation’s economic output. However, its production is decreased by fungal diseases such as Fusarium oxysporum induced root rot. The objective of this study is to evaluate the efficacy of fungal bio-agents in managing tea root rot in the tea-growing regions of Southwestern Ethiopia. Materials and Methods: Samples were taken from the Gumero and Wish-Wash tea plantation areas in Southwest Ethiopia. Using the dual culture method five bio agents namely Tg01, Tg02, Tg03, Tg04, Tg05, and three known Trichoderma spp. (Trichoderma harzianum, Trichoderma asperellum, and Trichoderma viride) were characterized and evaluated. These bio-agents were identified as fungal species. The ANOVA was conducted using SAS software (version 9.4), with arcsine transformation for data normalization and mean separation via the least significant difference at p = 0.05. Results: 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. Additionally, the isolates' inhibition percentages against the examined pathogen varied. Likewise, Tg01 and T. asperellum revealed the lowest (43.1%) and highest (92.9%) inhibitory percentages. The Trichoderma species, specifically T. harzianum, T. asperellum, and T. viride, exhibited the highest degree of inhibition against the target pathogen and the fastest radial growth when compared to the other isolates. Conclusion: The next stage of the study should be to choose and identify the best possible bio-control agents, followed by evaluation in the field and a greenhouse. Overall, the BCAs of the investigated isolates demonstrated positive and promising outcomes under in vitro evaluation of the target pathogen in this study.