Biocontrol Potential of Native Trichoderma Isolates Against Phytophthora infestans in Tomato (Solanum lycopersicum): Isolation, Characterization, and Antagonistic Efficacy

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ABSTRACT

Tomato (Solanum lycopersicum) is a globally significant crop, yet its production is severely hampered by soil-borne diseases, particularly late blight caused by Phytophthora infestans. This pathogen leads to substantial yield and quality losses, necessitating sustainable alternatives to chemical fungicides. The rhizosphere microbiome, especially Trichoderma species, plays a vital role in plant health by suppressing pathogens through antibiosis, competition, and mycoparasitism. This study aimed to isolate and characterize native Trichoderma strains from tomato rhizospheres in Dedo and Goma districts, Ethiopia, and evaluate their antagonistic potential against P. infestans. Forty samples were collected, yielding 36 P. infestans isolates from infected tomato tissues and 10 Trichoderma isolates from rhizospheric soil. Dual-culture assays revealed that Trichoderma strains Ju-TGDa-2, Ju-TGDb-3, Ju-TDWc-2, and Ju-TGDb-2 exhibited significant inhibitory effects, suppressing pathogen growth by 10.2–15% after three days, 38–43.4% after six days, and 58–61.4% after nine days. Morphological characterization confirmed their rapid growth and competitive dominance over P. infestans. Statistical analysis (ANOVA, DMRT) validated the efficacy of these strains, with Ju-TGDb-2 showing the highest inhibition (61.4%). The findings demonstrate that native Trichoderma isolates possess strong biocontrol potential against P. infestans, offering an eco-friendly alternative for managing late blight in tomato cultivation. Further field trials and molecular characterization are recommended to optimize their application in integrated disease management strategies.

Significance of the Study:

This study highlights the potential of native Trichoderma isolates as eco-friendly biocontrol agents against Phytophthora infestans, the causative agent of late blight in tomatoes. By identifying effective strains from Ethiopian rhizospheres, the research provides a sustainable alternative to chemical fungicides, promoting environmentally friendly agricultural practices. This could significantly reduce crop losses, enhancing tomato production and supporting integrated disease management strategies.

Summary of the Study:

This research isolated and characterized native Trichoderma strains from tomato rhizospheres in Ethiopia to evaluate their antagonistic effects against P. infestans. Ten isolates were obtained, and four strains exhibited substantial growth inhibition of the pathogen, with Ju-TGDb-2 showing the highest efficacy (61.4%). These findings suggest that native Trichoderma isolates can be used as effective biocontrol agents, offering a promising solution for managing late blight in tomatoes.