抄録
A leaf rotting disease of tea plant new to Japan was found at five locations in Shizuoka Prefecture in August and September, 1956. Necrotic lesions of dark brown colour appeared on young leaves, often covered the whole surface of the leaves and let them fall off. Abundant hyphae of the causal fungus were found inside and outside of the attacked leaf tissue.
Fructification of the fungus was formed on the surface of the neighbouring healthy stems or leaves as a thin, whitish membrane with powdery appearance. Hyphae there usually branched crosswise and typical cross-shaped cells were observed. Basidia scattered, not forming a continuous layer. Basidiospores were hyaline, one-celled, ovate to elliptical with a rostrum at the base, sized 7.0-12.0×4.0-7.5μ (9.6×5.6μ on the average). Sclerotia were not found anywhere on the diseased plants. From thsse observations the fungus was identified as a species belonging to the genus Pellicularia (Corticium, according to the old taxonomic system), though the species name has not been exactly determined yet.
The symptom of the disease was very much similar to that of the black rot known to be prevalent in India and Sri Lanka, and the causal fungus was also of the same genus as the causal fungi of black rot. The authors, therefore, considered this disease to be the same kind as the black rot in South Asia, and named it "kurohagusare-byo" in Japanese, meaning black leaf-rotting disease.
