Antagonistic effects of Trichoderma spp. isolated from Düzce agricultural soils on Fusarium oxysporum f. sp. lycopersici, the causative agent of tomato root and crown rot, under in vitro conditions

In this study, the antagonistic activities of Trichoderma spp. isolated from Düzce agricultural soils against Fusarium oxysporum f. sp. lycopersici (FOL), which causes collar and root rot of tomato, were investigated under in vitro conditions. In a quadruplicate culture test of antagonist candidate Trichoderma isolates isolated from 120 soil samples taken from agricultural fields, 10 isolates were determined to have antagonistic activity against FOL In dual culture tests, while isolates GYO1F1 and GY1B1-0 showed the highest antagonistic effect against mycelial growth of the FOL at 100% and 71.87%, respectively, followed by isolates GY1F1-0, GY2F2-0, KTM1-0, GK2F2-1, GY12F2-0, and GYO2F2-0 with antagonistic effects ranging from 10.9% to 31.06%. However, isolate KT1M1-2 exhibited the lowest antagonistic activity (3.26%). The volatile compounds of isolates GYO1F1 and GY1B1-0 inhibited the colonial growth of FOL by 13.37% and 38.45%, respectively, on the sixth day after inoculation using the dual Petri dish method. In the study, it was concluded that GYO1F1 and GY1B1-0 isolates, identified as T. virens by macroscopic and microscopic morphological identification, could be promising biological control agents against FOL.