Abstract
Three Valsae, namely Valsa cryptomeriae KITAJIMA (1918), V. cryptomeriaecola HARA (1925) (=V. cryptomeriae HARA, 1918) and V. sugifolia HARA (1918), have been described as the causal agents of a canker or a needle disease of Japanese cedar, Cryptomeria japonica D. DON. From the comparative studies on the herbarial and fresh materials of these Valsae (Table 1), the authors came to the conclusions that these three species of Valsa were nothing but the same species, and that its nomenclature should be V. cryptomeriae KITAJIMA. Though it is noted that V. cryptomeriae is quite similar to V. abietis FRIES recorded on various conifers in foreign countries in its morphological characteristics (Table 2), the possible identity of V. cryptomeriae with V. abietis is not concluded here.
Ascospore and pycnospore of V. cryptomeriae germinated well on 2% agar-agar and potato-sucrose agar, but pycnospore did not germinate in the distilled water in this test. Pycnospore swelled remarkably before germination (Figure 1, d). The fungus developed well into a mycelial colony on potato-sucrose agar and SAITO'S soy agar, and produced pycnidia on the one-month-old colonies. On the other three media tested, namely WAKSMAN'S agar, Cryptomeria-needle-decoction agar and corn decoction agar, the growth of the colony was poor and pycnidia were not produced after all (Figure 2). Optimum temperature for the growth of mycelial colony was about 20°C with the maximum of 30°C and the minimum of 5°C (Figure 3).
In the inoculation tests conducted from May to December, only the burning incision tests made in November and in December showed positive results and pycnidia were produced on the cankered area (Table 3).
