Blister blight a threatened problem in tea industry: A review

Tea is one of the most consumed beverages and is produced from the tender leaves of the tea plant. Various biotic and abiotic factors are directly related to tea productivity. Among the biotic factors the most destructive one is the blister blight disease of tea caused by an obligate parasitic fungus Exobasidium vexans Massee. The pathogen attacks the tender leaves of the tea plant which directly interferes with the economic growth of the tea growing countries as tea has tremendous export value. Numerous studies have identified the symptoms, epidemiology of the pathogen and its control strategies. Application of protectant and eradicant fungicides have shown promising results for controlling blister blight but overuse of chemical pesticides causes phytotoxicity, residual effects, thus use of microbial biocontrol agents are gaining more impetus. Different integrated disease management strategies along with modern emerging management approaches like elicitor mediated defense responses, development of transgenic tea plant, transcriptome study that induce many R-genes which ultimately provide innate immunity in tea plants. This review presents up-to-date information on blister blight disease which would help the future researchers to understand the host-pathogen interaction and the effective control measures to be adopt in a better way.