Biocontrol Potential of Trichoderma Species against Soil-born Tomato Pathogens (Fusarium oxysporum and Sclerotium rolfsii) in Senegal

Abstract

Soil-borne pathogens are major contributors to agricultural losses in developing countries. Trichoderma spp. are widely used as biocontrol agents for the management of fungal diseases of crop plants, due to their strong antagonistic activity and mycoparasitic abilities against a broad range of phytopathogens. The present study aims to evaluate the antagonistic potential of Trichoderma strains against two major tomato pathogens, Fusarium oxysporum and Sclerotium rolfsii. Seven Trichoderma asperellum strains and one Trichoderma virens strain collected from the Niayes tomato-growing zone in Senegal were characterized for their antagonistic activity against Fusarium oxysporum and Sclerotium rolfsii. Dual culture and the sealed Petri dish techniques were used to evaluate the percentage inhibition of pathogens by Trichoderma strains. All Trichoderma strains exhibited antagonistic activity and significantly inhibited the in vitro mycelial growth of Sclerotium rolfsii and Fusarium oxysporum. In direct confrontation assays, strain TM1 showed the highest inhibition rate against F. oxysporum (73.49 %) while strain TN1 exhibited the highest performance against S. rolfsii (59.26 %). In indirect confrontation assays, strainTG4 showed the highest inhibition rate against Sclerotium (31.37 %), whereas TM1 showed the highest inhibition rate against Fusarium (39.11 %). Overall, inhibition rate observed in direct confrontation assays were higher than those recorded in indirect confrontation test. Furthermore, Fusarium oxysporum appeared to be more sensitive to the antagonistic activity of the Trichoderma than Sclerotium rolfsii.