松葉枯病の病原菌とその生理的性質

This paper deals whith the results of invetigations on the pathogen of leaf spot of pine seedling and its physiological and pathological studies.
Macrophoma pini-densiflorae SAWADA, Pesta-lotia shiraiana P. HENN. and phoma sp. were isolated from the diseased pine leaves.
The optimum temperature and hydrogenion concentration for a germination of pycno-spore seemed to lie at aproximately 20℃ and pH 4.2 in Macropohoma, and 25℃, pH 6.4 in Petalotia, respectively. The germination of pycnospores of Macrophoma and Pestalotia in the pine leaf decoction was promoted than in distilled water. The optimum conditions of mycelial growth of Macrophoma were at 25℃, pH 4.0 and of Pestalotia at 25℃, pH 3.0-5.8. Favorite growth of both fungi was observed in Saito's soy souce agar medium.
The pathogenicity of Macrophoma was recognized on the pine seedlings but no pathogenicity of Pestalotia was observed on them except of artificially wounded ones.