Evaluation of trichoderma Spp. isolated from southern indian tea plantations against phomopsis canker disease

Abstract

Tea, the most popular beverage, obtained from the flush shoots of the plant Camellia sinensis (L). O. Kuntze. It is being considered to be the chief commercial crop in India and it occupies a vital place in national s economy. Humid climatic conditions and heavy rainfall lead to the exposure of many fungal diseases, among which Phomopsis canker caused by a fungal pathogen, Phomopsis theae Petch is the major constraint and leads to considerable economic losses in tea plants. Infected bushes alter the plant metabolism and subsequently causes to plant death. Despite of its economic impact, effective preventive measures are not available other than pruning of healthy wood and application of copper fungicides on prune cuts to tea plants. However, it may adversely affect the environment, soil and non-targeted organisms. The application of biocontrol agents could be an alternative to chemicals in the management of Phomopsis canker disease in tea plants. Trichoderma spp. are soil borne, saprophytic fungi investigated as potential biocontrol agent and capable of reducing the incidence of common soil borne pathogens like P.theae. They are highly interactive in roots, soils and foliar environments and can able to synthesis metabolic compounds which have inhibitory effects on various pathogens. It has been reported that indigenous isolates are more effective with enhanced adaptability in controlling the phytopathogens than commercial bioagent that are made available in the market. The present study deals with development of an efficient indigenous biocontrol agent like Trichoderma atroviride against P.theae to control the disease incidence in southern India tea plantations. The rhizosphere soil samples were collected from a total of 30 commercial tea planting estates covering six major planting districts of southern India viz., iv Valparai, Coonoor, Munnar, Vandiperiyar, Gudalore and Koppa and subjected to analysis various soil edaphic and environmental parameters.