Leaf diseases are very important in tea production since the plants are grown for their young leaves. The major foliar disease of tea in Asia is blister blight. Wind-borne spores germinate on the leaf in humid conditions and the leaf is penetrated. Further growth presses out and eventually a blister is formed on the leaf. Each blister can produce up to 20 million spores. Tea prepared from blistered leaves is weak, with poor color, aroma, brightness, and briskness. Before the use of fungicides, tea losses to blister blight were staggering with 30-50% losses. Preventive copper sprays have been the mainstay of tea production for the past 60 years. Blister blight is not a problem for organic tea growers since they are permitted the use of copper sprays.
“Tea is one of the most popular beverages in the world owing to its taste, the stimulative effect, and also for its health benefits. Perennial habit of the tea plant, peculiar cultural conditions and warm humid climate of the tea growing areas are highly conducive for disease development… Among the leaf diseases, blister blight caused by Exobasidium vexans is the most important one. The disease is known to occur in almost all tea growing areas of Asia. E. vexans is an obligate parasite with no alternate host. Hence, its life cycle has to be completed on tea plant itself. The entire life cycle is completed in 11 days under conducive weather conditions or else it could extend up to 28 days… Comparisons between the crop harvested from tea fields protected by fungicide spray and those left unsprayed indicated a loss of 50% to blister blight disease in six months.”
Authors: Sowndhararajan, K., et al.
Affiliations: School of Life Sciences, India.
Title: Integrated control of blister blight disease in tea using the biocontrol agent Ochrobactrum anthropi strain BMO-111 with chemical fungicides.
Source: Journal of Applied Microbiology. 2013. 114:1491-1499.