Abstract
Using mulberry seedlings grafted by diseased stems collected from Gumma and Shiga Prefectures, the mode of symptom appearance of mulberry mosaic disease was examined, when temperature was regulated 15, 23 and 31°C, respectively.
As a rule, plants grown at 23°C and 31°C showed symptoms while symptoms were almost masked at 31°C. Intensity of symptom at 23°C was higher than that at 15°C.
Some of the symptoms on plants kept at 31°C were thickening and hardening of leaves and veinclearing that were considered to be primary symptoms of enation.
When plants were kept at 15°C, conspicuous mosaic and a very few ring spot symptoms were shown on leaves. Mosaic was also considered to be primary symptom of enation, because typical enation has further appeared on some of the lightcolored portions of mosaic leaves.
Mode of appearance of symptoms on the plants kept at 23°C was very complicated and was variable according to the places collected diseased stems and the growing stage. On the materials from Gumma Prefecture, severe enation developed on the leaves in all growing stage, and few other symptoms were observed. On the materials from Shiga Prefecture, various symptoms, i. e., mosaic, enation, ring spot and yellowing spot, appeared, and transition of appearance of these symptoms showed variation to growing stage.
