First report of whisker mold, a postharvest disease on citrus caused by Penicillium ulaiense (in Japan)

In March 2006, stored fruits of the medium-to-late-ripening citrus variety Shiranuhi ([Citrus unshiu x C. sinensis] x C. reticulata) were found to have a disease similar to blue mold. The fungus causing this disease differed distinctly from the well-known, blue mold agent, Penicillium italicum, because it formed whisker-like coremia measuring 1-8 mm. On the basis of the morphological characteristics and the phylogenetic analysis based on the nucleotide sequence of the beta-tubulin gene, the fungus was identified as P. ulaiense. This is the first report of citrus whisker mold caused by P: ulaiense in Japan.