Use of Rhizospheric Microbes for Developing Plant Growth in Tea Nursery and Controlling Red Rust Disease of Tea Caused by Ceplaleuros parasiticus Karst, in Bangladesh

Abstract

Assessment of plant growth promoter and biocontrol properties of plant growth promoting rhizomicroorganisms (PGPR) from tea soil against red rust disease of tea caused by Cephaleuros parasiticus Karst, in Bangladesh was conducted. The microbes were isolated from soils of tea fields and cultured on different nutrient media. The microbial strains were inoculated with tea nursery soils by mixing with 50 g of decomposed cow dung. In tea plantations, the microbial strains were sprayed on diseased plants two times at 15 days intervals. Four PGPR strains Bacillus, Pseudomonas, Streptomyces, Trichoderma were isolated from the rhizospheric soil of tea. Streptomyces significantly responded to increasing 21.95% leaves, 18.77% plant height, and 26.14% stem girth over the control followed by Pseudomonas and Trichoderma. These PGPR strains enhanced plant growth in nursery and positively affected the rate of increased number of leaves, plants’ height and plants’ girth by 33, 43 and 3%, respectively. The lowest severity (21.00) was found with Trichoderma after 35 days after spraying followed by Bacillus, Pseudomonas and Streptomyces with identical values. Trichoderma and Bacillus cause 16 and 14% reduction of disease severity, while both Pseudomonas and Streptomyces cause 10%. All the microbes have a great impact in reducing disease severity by 19% with optimistic relations. The biofertilizer showed a comparatively lower response in reducing disease severity. It can be decided that Bacillus, Pseudomonas, Streptomyces and Trichoderma isolated from tea soil have their growth capacity as well as decrease the disease severity of Red rust disease of tea fields.