Effect of chemicals and biological agents on branch canker disease in tea

Abstract

Branch canker caused by Macrophoma sp. is the most wide spread and serious stem disease of tea plants.In this study, we tried to determine the bioefficacy of different chemical fungicides and indigenous biological strains on branch canker disease in tea plant under glasshouse condition. The infected stem portions were collected and identified through 18S rRNA molecular methods. Bacterial strains were isolated from different tea growing areas and confirmed by16S rRNA technique. Fungal biocontrol strains were obtained from repository Microbial Type Culture Collection and Gene Bank(MTCC), Chandigarh, India.Among the fungicides tested,benomyl (70%) showed better results followed by copper oxychloride (65%). The biocontrol agentsBacillus sp. (50%) and Trichoderma viride (50%) yielded significant results. Pseudomonas sp. showed moderate activity (45%)followed by Trichoderma harzianum (30%). The integrated combination approach,propiconazole/Bacillus amyloliquefaciensand propiconazole/B. subtilis recorded effective control against branch canker disease under greenhouse condition followed by hexaconazole/B.amyloliquefaciens.Combination of fungicides companion (0.70), hexaconazole (0.63) and propiconazole (0.67) were found to be most effective. The organic fungicide tricure gave satisfactory control followed by Gliocladiumvirens against branch canker disease.