தாவர நோயியல் & நுண்ணுயிரியல் இதழ்

சுருக்கம்

In vitro Studies on Branch Canker Pathogen (Macrophoma sp.) Infecting Tea

Mareeswaran J, Nepolean P, Jayanthi R, Premkumar Samuel Asir R and Radhakrishnan B

Branch canker is the main stem disease of Camellia sp. caused by Macrophoma sp. In this study, branch canker pathogen was isolated, bought to pure culture and maintained in potato dextrose agar medium (PDA). A total number of 150 bacterial and 40 fungal strains were isolated from different agro climatic zone of south India, which are region specific and native strains (resembling Pseudomonas spp. Bacillus spp. and Trichoderma spp.). Among the total number of bacterial and fungal isolates, 6 bacterialand 3 Trichoderma spp. Showed antagonistic effect against the branch canker pathogen. The study clearly indicates that Bacillus spp. Pseudomonas spp. followed by Trichoderma spp. showed higher antagonistic potential against the test pathogen. The study also includes that, the selected botanical fungicides, neem kernel extract, garlic extract, Aloe vera, Tulsi and Expel (Botanical fungicides) at different concentration were carried out against Macrophoma sp. Results showed that, commercially available botanical fungicide (Expel) is effective to control the growth of branch canker pathogen compare then other chemical and botanical fungicides. The commonly used fungicides in tea plantation such as Hexaconazole (Contof 5E), Tebuconazole (Folicur) and Tridemorph (Calixin) were evaluated against Macrophoma sp. under in vitro conditions. The results indicated that Tebuconazole all the three concentrations at 1.78 ppm was found to be the most effective in suppressing the growth of branch canker pathogen. The results concluded that biocontrol agents (Bacillus spp. Pseudomonas spp and Trichoderma spp.), botanical fungicide (Expel) and chemical fungicide (Tebuconazole) are very effective to control the branch canker pathogen under in vitro conditions.