Abstract
In 2007, black spots that appeared on the surface of the rhizomes of ginger (Zingiber officinale Rosc.) during storage caused serious losses in Kochi Prefecture, Japan. Most of the black spots formed at the joints of the rhizomes. A fungus was frequently isolated from the symptomatic rhizomes. The isolate caused the same symptoms on artificially inoculated ginger rhizomes and was reisolated. The fungus formed white stellate colonies with a greenish black spore mass on PDA. Mycelia grew on PDA from 10°C to 35°C with maximum growth at 30°C. Sporangia were fusiform, monocellular, and 7.5–5.0×2.0–3.0 (average 6.4×2.5) µm. The morphology of the fungus agreed with that of Myrothecium verrucaria (Albertini et Schweinitz) Ditmar. The nucleotide sequence of the r-DNA ITS regions agreed well with those of M. verrucaria. In conclusion, the isolate was identified as M. verrucaria. This is the first report of a disease of ginger caused by M. verrucaria, and we propose to designate the disease as myrothecium rhizome spot of ginger.
