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.
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