ネギに葉枯病を起こすStemphylium vesicarium

抄録

Two fungal species, Stemphylium sp. and Pleospora sp., were found on leaves of Welsh onion showing leaf blight symptoms in commercial fields in Konoura, Akita, from September to October 1999. Fungi isolated from the single conidium and ascospore showed pathogenicity to Welsh onion by artificial inoculation. Conidia of the two fungi from Welsh onion on both V-8 juice agar medium and lesions on the crop inoculated with them were identical to those of Stemphylium sp. Morphological studies showed that the conidial state of these fungi is S. vesicarium (Wallroth) E. Simmons. The teleomorph observed in cultures of the isolate from Stemphylium sp. was identical to naturally occurring Pleospora sp. The results indicate that these fungi is the same. Since S. botryosum has only been recognized as the causal fungus of leaf blight in the Welsh onion in Japan, we suggest that S. vesicarium (Wallroth) E. Simmons (teleomorph: Pleospora allii (Rabenh.) Ces. & De Not.) is an additional pathogen of the disease.