Agricultural Biotechnology Journal

Agricultural Biotechnology Journal

Integrated biocontrol of okra root rot caused by Fusarium solani and Macrophomina phaseolina using Pseudomonas fluorescens and Saccharomyces cerevisiae

Document Type : Research Paper

Authors
Ahmed Falih Shamukh
Norien Abdulzahra Hasan
Wedad Marid Hamood
Qusai Hattab Madhi
Plant Protection Department, College of Agriculture, University of Misan, Iraq.
10.22103/jab.2026.27237.1913
Abstract
Objective
This study evaluated the antagonistic potential of the yeast Saccharomyces cerevisiae and the bacterium Pseudomonas fluorescens against Fusarium solani and Macrophomina phaseolina, the causal agents of okra (Abelmoschus esculentus L.) root rot and seedling damping-off. The research involved isolation and identification of the pathogens, assessment of their pathogenic variability, and evaluation of biological control agents under laboratory and greenhouse conditions.
Materials and methods
Three isolates of F. solani and two isolates of M. phaseolina were obtained from infected okra plants collected from different locations. Significant variation in pathogenicity was observed among the isolates. The isolate F1 of F. solani exhibited the highest virulence, causing a significant reduction in seed germination and increasing seedling mortality by 43.2% and 49.4%, respectively, compared with the untreated control.
Results
In vitro assays demonstrated that P. fluorescens effectively inhibited the radial growth of F. solani and M. phaseolina by 48.36% and 64.7%, respectively. Similarly, S. cerevisiae exhibited significant antifungal activity, particularly at the fifth dilution, where growth inhibition reached 74.1% for F. solani and 76.1% for M. phaseolina. These findings demonstrate that both biological agents significantly suppressed fungal growth under in vitro conditions. Pathogenicity tests confirmed that infection with F. solani and M. phaseolina significantly reduced seed germination and increased seedling mortality. However, application of biological treatments reduced disease severity. Among all treatments, the combined application of M. phaseolina with P. fluorescens produced the best results, significantly improving germination percentage and reducing seedling mortality compared to pathogen-only treatments. Greenhouse experiments further revealed that both S. cerevisiae and P. fluorescens, applied individually or in combination, significantly enhanced seed germination, chlorophyll content, vegetative growth, and leaf area. Moreover, the combined treatment exhibited a strong synergistic effect in suppressing pathogen activity, reducing disease incidence and severity, and promoting overall plant growth performance.
Conclusion
Overall, the results of this study demonstrate that S. cerevisiae and P. fluorescens are promising eco-friendly biological control agents that can be effectively used in integrated management strategies for controlling okra root rot disease caused by F. solani and M. phaseolina. These findings support the development of sustainable disease management approaches that reduce reliance on chemical fungicides while improving plant health and productivity.
Keywords
Biocontrol agents
Fusarium solani
Macrophomina phaseolina
Pseudomonas fluorescens
Saccharomyces cerevisiae
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Agricultural Biotechnology Journal
Volume 18, Issue 4
Summer 2026
Pages 425-438