Necrotic lesions were found on the leaves and stems of Japanese white oak (Quercus myrsinifolia) seedlings on a nature trail in Japan. A species of Phytophthora was isolated from the necrotic lesions and adjacent soil. Molecular phylogenetic analysis and morphological examination revealed it to be Phytophthora castaneae, known as a causal pathogen of trunk rot on chestnuts. Pathogenicity testing showed that P. castaneae caused leaf blight on previously healthy Japanese white oak seedlings. In addition, using a soil infestation method, we confirmed that it was also pathogenic to chestnut seedlings, but the roots of Japanese white oak were not infected. This is the first report of P. castaneae causing disease in a natural ecosystem in Japan.

在日本的一条自然小径​​上，日本白橡树 ( Quercus myrsinifolia ) 幼苗的叶子和茎上发现了坏死病灶。从坏死病斑和邻近土壤中分离出一种疫霉菌。分子系统发育分析和形态学检查表明它是栗疫霉，是板栗树干腐病的致病病原体。致病性测试表明，栗疫霉引起了先前健康的日本白橡树幼苗的叶枯病。此外，利用土壤侵染方法，我们确认它对板栗幼苗也有致病性，但日本白橡树的根部没有被感染。这是日本首次报道栗疫霉在自然生态系统中引起疾病​​。