Background: Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici (FOL), is a devastating soil-borne disease of tomato that causes severe yield losses. The phasing out of chemical soil fumigants necessitates sustainable biological alternatives.

Objective: This study aims to compare the efficacy of two biocontrol agents-Trichoderma harzianum and Bacillus subtilis-in suppressing Fusarium wilt and promoting plant growth under controlled greenhouse conditions.

Method: This study uses a simulated dataset created for academic training purposes. A simulated completely randomized design (CRD) was generated with four treatments: Control, FOL only, FOL + T. harzianum, and FOL + B. subtilis. Disease severity (- scale), plant height, and biomass were recorded over 60 days. Data were subjected to ANOVA in R.

Key Results: Inoculation with T. harzianum significantly reduced disease severity by 68% compared to the FOL-only treatment, whereas B. subtilis reduced severity by 52%. T. harzianum also demonstrated superior plant growth promotion, increasing fresh biomass by 45% over the pathogen control.

Conclusion: Trichoderma harzianum exhibits high potential as an effective biocontrol agent for managing Fusarium wilt in tomatoes, offering both disease suppression and growth enhancement benefits.