Ponnuchamy Ponmurugan
K. S. Rangasamy College of Technology, India
Title: Biological control of a phytopathogen Phomopsis theae under laboratory, greenhouse and
Biography
Biography: Ponnuchamy Ponmurugan
Abstract
Interaction between the pathogen Phomopsis theae and bacterial antagonist namely Pseudomonas fluorescence, fungal antagonist like Trichoderma atroviride and actinomycetes antagonist namely Streptomyces sannanensis was studied under in vitro condition. Antibiosis was performed to analyze the secondary metabolites produced which have the antagonistic properties for the pathogenic agents used in the present study. The biocontrol agents used were evaluated against C. theae in both solid media and liquid media to determine the suppressing growth rate. The result indicated that actinomycete antagonist was found to be effective when compared to the bacterial and fungal antagonist respectively in terms of pathogen’s growth suppression and further the mix of consortia served to be most effective. The growth inhibition rate recorded was 85.5% in actinomycete antagonist treated plates and 77.3 and 68.8% in bacterial and fungal treated Petri plates; respectively against the pathogen. After laboratory screening, attempts were made to evaluate the efficacy of these biocontrol agents for controlling red root rot disease of tea plants. Among the thirteen treatments tested, soil drenching of carbendazim was superior in terms of reducing red root rot incidence followed by combination of S. sannanensis and T. atroviride recorded in two consecutive field experiments. In contrast, the maximum green leaf yield and plant growth was achieved in soil application of these biocontrol agents. However, the performance of this dual combination of biocontrol agents was on par with systemic fungicide in terms of disease control. The biometric, physiological and biochemical parameters were considerably increased in biologically treated plants when compared to untreated control. Moreover, studies were undertaken to investigate the effect of abiotic and abiotic factors on the survival rate biocontrol agents in soils which revealed all the tested bioagents could survive well in tea soils as well as barks. The present study may be concluded that biocontrol agents could be a possible alternative control measures for the control of P. theae, which in turn reduces the organic chemical residual risk in made tea and it totally improves the tea ecosystem.