Variation in Symptoms of Bacterial Shoot Blight of Tea Plant

Abstract

Bacterial shoot blight of tea caused by Pseudomonas syringae pv. theae is a disease which attacks several cultivars including Inzatsu 131 producing deep brown necrotic lesions on leaf blades, petioles and stems. In July 1983, however, new symptoms were detected on the undersurface of the leaves of cv. Yabukita in Shizuoka Prefecture. They were characterized by light brown and shallow necrosis limited to the lower epidermis and a few layers of subepidermal spongy parenchyma cells. The causal bacterium was identified as P. syringae pv. theae. The results of inoculation tests at different temperatures suggested that this bacterium induces diverse symptoms on tea leaves depending on the climatic conditions as well as the kinds of cultivars.