Occurrence, Distribution, Consequence, Biology and Management of Tea Blister Blight (Exobasidium vexans Massee): A Review

Abstract

Tea (Camellia sinensis) is one of the most commonly consumed beverages next to water by a wide range of age groups in all levels of society in the world. Tea blister blight caused by Exobasidium vexans is a devastating disease that causes severe damage to tea in major Tea producing countries of Asia. The disease causes a crop loss as high as 50% and adversely affects the quality of made tea. It is reported throughout the tea growing countries of Asia, especially in India, Sri Lanka, Indonesia, Malaysia, Thailand, Philippines, Taiwan and Japan. It infects the young leaves of tea bush. In the field, Blister blight appear as circular blisters pale yellow spots first and turned to circular white spot later on tea leaves. Basidia of E. vexans are clavate to cylindrical, 88.6-164.5 × 3.8-5.1 μm with ellipsoid to ovoid, 11-16 × 4-6 μm, hyaline, smooth, one-septated basidiospores. The increased disease severity on tea decreases yield, deteriorates quality and declines total phenols, catechin, total nitrogen, amino acids, chlorophylls and polyphenol oxidase activity in tea.  Use of improved cultural practices (Pruning of tea bushes), biological control by use of parasitic bacteria (Pseudomonas fluorescens), use of resistant tea clones and chemical control by use of fungicides Hexaconazol, Copper Oxychloride, Propiconazole, Bitertanol, Carbendazim, Hexaconazol, Tridemorphs, Triazoles and Nativo play a role in the disease management.

Keywords: Asia, brown spot, crop loss, white velvet, young leaves, Tea bush

DOI: 10.7176/JBAH/12-19-04

Publication date:October 31^st 2022