In the 1970s, a new high-yielding green tea variety – Yabukita – was introduced in Japan and has been wildly popular because of quality attributes that Japanese tea drinkers favor, including the characteristic “umami” savory taste. This one-cultivar industry led to prevalent and frequent outbreaks of tea plant diseases which has resulted in a dependence on regular fungicide applications.

“Tea is one of the most important cash crops in the warm southwest areas of Japan. The green tea cultivar ‘Yabukita’ has been cultivated since the 1970s and grown in about 75% of all tea fields in Japan. Using a monoculture cultivation system, new Yabukita tea shoots can be harvested synchronously, producing green tea of consistent quality. However, this system has resulted in severe pest problems such as outbreaks of tea anthracnose … and tea gray blight … Therefore, repeated spraying of fungicides is needed to protect tea plants against both the diseases for each tea crop.”

Authors: K. Yoshida, A. Ogino, K. Yamada and R. Sonoda
Affiliation: National Institute of Vegetable and Tea Science
Title: Induction of disease resistance in tea (Camellia sinensis L.) by plant activators.
Publication: Japan Agricultural Research Quarterly. 44(4):391-398.