Introduction: Roselle is a wet rot in Gabon caused by Phoma sabdariffae Sacc., a deuteromycete fungus of the family Phomaceae. The chemical control used for its eradication has had many limitations, including the appearance of fungal resistance and the persistence of chemoactive substances. Objective: The present study was initiated to test an alternative control solution, by the use of a toxic plant, Tephrosia vogelii. Methods: For this purpose, this plant was macerated, and the solutions transferred to PDA solid culture media, to constitute 4 treatments: T5 (5%), T10 (10%), T15 (15%) and T20 (20%). Fungal spores were cultured in the center of petri dishes, and mycelial growths measured every 2 days for 10 days. Results: The results revealed that all the modified treatments in solution of Tephrosia vogelii reduced the mycelial growth of Phoma sabdariffae. The most pronounced reductions were produced by the T15 and T20 treatments, with the respective inhibition rates of 81% and 100% at the 10th day of incubation. Conclusion: The use of concentrated extracts of Tephrosia vogelii is therefore possible in the biological control of roselle rot in Gabon.