Effect of Salicylic Acid and Benzothiadiazole on Control of Tea Blister Blight
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Date
2013
Journal Title
Journal ISSN
Volume Title
Publisher
Uva Wellassa University of Sri Lanka
Abstract
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:
Description
Keywords
Agriculture, Export Agriculture, Crop Production, Tea Industrials, Tea Technology