Browsing by Author "Nuwani, W.W.S."

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    Effect of Salicylic Acid and Benzothiadiazole on Control of Tea Blister Blight
    (Uva Wellassa University of Sri Lanka, 2013) Nuwani, W.W.S.; Chandrasena, G.; Sinniah, G. D.
    Blister blight caused by the obligate parasitic fungus Exobasidium vexans Massee is seriously affects the production by reducing quality and the quantity. Control of blister blight heavily depends on synthetic fungicides. Large-scale application of pesticides pollutes the environment and their residues can cause various health hazards to human beings. Therefore, use of environmentally friendly chemical in disease control strategies is gaining importance. Elicitors are low toxic chemicals that can be integrated into blister blight disease management. The objective of this study was to determine effect of Salicylic acid (SA) and 2, 1, 3- Benzothadiozole (BTH) on control of tea blister blight diseased caused by E. vexans Massee. Methodology TRI 2024, a susceptible cultivar to blister blight was treated with 1000 ppm SA, 1000 ppm BTH, 0.1% Copper hydroxide (Champ DP 37.5%), 0.05% Hexaconazole and untreated control at seven day intervals for four weeks under field conditions. The experimental design was Randomized Complete Block Design with four replicates in each treatment. leaves was assessed seven days after application of the chemicals. Harvestable shoots were collected separately from each plot and 100 shoots were selected randomly for each plot and assessed for Blister blight severity using a Blister assessment key where 0= No translucent spots, 1= Hypersensitive reaction (HR), 2= Blister >5% of total leaf area, if only translucent spots appear it covers 2-15% leaf area, 3= Blister cover >5% of total leaf area, if only translucent spots appear it covers 2-15% leaf area, 4= Blister cover 5-15% total leaf area, if only translucent spots appear, it covers >15% leaf area, 5= Blister cover 15 -30% of leaf area, 6= Blisters cover >30 leaf area and stem is infected. Disease severity was calculated according to the following formula: