The effectiveness of Trichoderma asperellum strain DN7.5 in controlling bacterial wilt disease caused by Ralstonia pseudosolanacearum T2C-Rasto on cucumbers in vivo conditions

Bacterial wilt disease, caused by Ralstonia solanacearum, causes significant loss to cucumber production in the Mekong Delta. In this study, the antibacterial activity of 95 strains against Ralstonia pseudosolanacearum strain T2C-Rasto was tested by the agar well method. Under laboratory conditions, three Trichoderma strains involving DN7.5, DN2.6, and DN30.7 showed strong inhibitory activity against Ralstonia pseusolanacearum strain T2C-Rasto with effectiveness of 74.29, 67.63, 67.63%, respectively. Under In vivo conditions, Trichoderma strain DN7.5 showed the highest effectiveness against Ralstonia pseusolanacearum strain T2C Rasto, reducing disease incidence by 26.67% after 14 days without affecting cucumber plant growth. The ITS (internal transcribed space) + 26S rRNA gene region of Trichoderma strain DN7.5 showed 98.13 - 98.38% sequence similarity with ITS sequence of Trichoderma asperellum strains (MF363050.1 - OM515036.1). Generally, Trichoderma strain DN7.5 has the potential for further research on the mechanisms of suppression against Ralstonia pseusolanacearum strain T2C-Rasto.