Potential of Trichoderma spp. as Biological Control Agents Against Bakanae Pathogen (Fusarium fujikuroi) in Rice

Bakanae disease is a major rice disease caused by Fusarium fujikuroi. Infected plants show slender and hyper elongated internodes due to the over-production of gibberellic acid. Application of Trichoderma spp. as biocontrol agent is gaining attention due to high capability in hyperparasitize the soil borne pathogen. The studies aimed to screen and evaluate the bio-efficacy of Trichoderma spp. with antagonistic activities against F. fujikuroi and plant growth-promoting properties. All the 65 Trichoderma isolates were isolated from healthy rice rhizosphere soil. Thirty eight out of 65 Trichoderma isolates exhibited more than 45 Percentage of Inhibition Radial Growth (PIRG) against F. fujikuroi in dual culture plate testing. All selected Trichoderma isolates were further in vitro screened for antagonistic testing: volatile compounds production and hydrogen cyanide production and plant growth-promotion properties: IAA production and phosphate solubilization. Twelve Trichoderma isolates were selected for further evaluation on antagonistic activity against F. fujikuroi, germination rate, plumule and radical lengths and vigor index. Finally, seven of the most potential Trichoderma isolates were selected for greenhouse evaluation. The bakanae disease incidence and disease severity in rice plant treated with respective selected Trichoderma isolates were significant reduced as compared with untreated plant. However, there was no significant increase in plant height between Trichoderma inoculated and uninoculated plants. Moreover, rice plant treated with Trichoderma T61 showed significantly increase in total plant dry biomass as compared to untreated plants. The selected Trichoderma isolates have potential to be developed as biological control agent against F. fujikuroi and also as an alternative for bakanae management.