Abstract
A slimy rot symptom was found on the potato tubers transported from Hokkaido (Abashiri) to Tokyo. The symptom appeared only on the tubers which has been washed with tap water immediately after harvest and packed in plastic bags, but did not appear on unwashed ones. Same symptom was observed on the potato tubers piled up temporarily at the fields or on the seed-tubers stored in the air-conditioned store house (5-10C) for several months. Causal organisms were identified as pectolytic clostridia based on their bacteriological properties which will be reported in a succeeding publication. Pectolytic clostridia were detected on most of potato tubers collected from various potato fields in Japan. Not only on harvested matured tubers, they were also found on young and small tubers in their early growth stages. Slimy rot and gas production in rotten tubers are important criterions to distinguish this disease from soft rot which is caused by Erwinia spp., though other symptoms are almost similar. The name of “slimy rot” was proposed for this new post-harvest disease of potato tuber.
