Pallavi R.V.,UPASI Tea Research Institute Valparai |
Nepolean P.,UPASI Tea Research Institute Valparai |
Balamurugan A.,UPASI Tea Research Institute Valparai |
Jayanthi R.,UPASI Tea Research Institute Valparai |
And 2 more authors.
Asian Pacific Journal of Tropical Biomedicine | Year: 2012
Objective: To isolate the biocontrol agents and their fungicides tolerance against grey blight disease in tea. Methods: Grey blight is the leaf disease of Camellia sinensis (C. sinensis) caused by fungus Pestalotiopsis sp. Grey blight pathogen was isolated from infected leaves of tea plant from different agro climatic zone of southern India. A total number of 320 bacterial strains were isolated from various soil samples, among these isolates, three Bacillus (MB1, MB2 and MB3), three Pseudomonas (MP1, MP2 and MP3) which showed higher antagonistic effect was taken for study. Production of cell wall lytic enzymes by the selected biocontrol isolates were studied by using mineral salt medium (MSM) with various carbon source (0.1%). All the selected isolates (MB1, MB2, MB3, MP1, MP2, and MP3) utilized all the substrates used. Fungicide tolerances of the selected bacterial strains were studied in vitro. The commonly used fungicides in tea plantation such as hexaconazole, carbendazim, mancozeb and copper oxy chloride (COC) were tested in three concentrations. Results: The results clearly indicated that the isolated biocontrol agents were capable of producing cell wall lytic enzymes which is the main mechanism in bacterial biocontrol agents. All the six selected biocontrol strains showed growth tolerance in carbendazim followed by hexaconazole. No growth was observed in COC and mancozeb. Conclusions: From this study it was concluded that the isolated biocontrol were tolerant to commonly used fungicides carbendazim and hexaconazole against grey blight disease. © 2012 Asian Pacific Tropical Biomedical Magazine. Source