Abstract
To clarify the causal fungus of butt rot disease of Cryptomeria japonica (Sugi), we isolated basidiomycetous fungi from decayed stumps in 12 plantations 40 to 83 years old in the Aso district, Kumamoto Prefecture, Japan, and characterized two major fungi isolated. In the plantations studied, eight kinds of basidiomycetes having different morphological characteristics were isolated from rotted stumps, two of which were the major fungi. Basidiomycete-A was isolated at a relatively high frequency only in one plantation at Minami-Oguni. On the other hand, Basidiomycete-B was isolated at a high frequency in all plantations surveyed, which suggested that this fungus was widely distributed throughout the Aso district. The wood block decay test confirmed that both Basidiomycete-A and -B have ability to decay wood block. From the results, we concluded that Basidiomycete-A and/or -B were responsible, at least partly, for butt rot disease of C. japonica in the Aso district.
