Studies on the Grape Anthracnose, Elsinoe ampelina : 1 . Cultural Aspects of the Fungus

Some characters of the grape anthracnose fungus, Elsinoe ampelina SHEAR, on various media were studied. 1 . Mycelia of Elsinoe ampelina grew very slowly on media. Colonies of the fungus were compact and upheaved at the central portion. The morphological appearance of the colony varied according to cultural conditions or components of media. 2 . Mycelia of the fungus developed sufficiently at temperatures ranging from 25 to 30C with the optimum at 28C. At 51C and 35C, no mycelial growth occurred even after 20 lays. The favorable hydrogen-ion concentration for mycelial growth seemed to be at pH 4. 6 7. 0, and the optimum was shown to be at pH 6. 0-7.0. The mycelial growth was suppressed at pH 3. 0 or below and pH 8. 6 or more. 3 . During the incubation of this fungus, pH values of almost all liquid media tested, especially those of media containing sucrose of low concentration, increased gradually. The pH value of the Tochinai-Nakano's medium with 1 %-sucrose changed from 5.6 to 9.5 after 18-day incubation, and that of the same medium with 3 % or 5 %sucrose changed to 8. 5 after 18-day incubation. 4. The growth of the fungus was the best on the media added with sucrose, maltose, or mannitol, and it was good on the media added with fluctose or dextrin. The effect of soluble starch, lactose or glyceline on the growth of the fungus was less than effects of the other carbon sources. 5. The growth of the fungus was the best on the media added with asparagine, and good with pepton, NaNO3,Ca(Nos)2 or KNO3 among media added with 11 nitrogen compounds. The effect of (NH4)2SO4 or NH4 Cl on the growth of the fungus was inferior compared to the effects of five nitrogen compounds above mentioned. Lower pH value in media containing ammonium salts seemed to cause an unsuitable condition for the growth of the fungus. 6. Comparative experiments of the growth of the fungus on various media containing some natural plant resources were carried out. The growth of the fungus was the best on the potato sucrose agar medium, and good on the media containing extracts of grape leaves, grape berries, or pea-pods. The growth on the potato extract agar medium was the worst. (Received July 1 , 1974)