Abstract
Invasion of Shiitake bed logs by Armillaria spp. was investigated in Uryu Experimental Forest of Hokkaido University. About 50% of the bed logs were invaded by rhizomorphs of Armillaria spp. The percentages of invasion in blocks are from 4.1 to 93.0, but showed the difference according to the blocks of the bed logs. It is considered that the bed logs were directly invaded by rhizomorphs of Armillaria spp. living in soil.
