Cultural characteristics of biological species of Armillaria from Hokkaido, Japan

tt~* ~~ lEA * t;(§!b rW!m n3§'* 1i +Jtt:t:§x Summary Mycelial growth and rhizomorph formation of Armillaria species from Hokkaido were studied on different media. Armillaria ostoyae, A. jezoensis, A. sinapina, A. sin­ gula and A. mellea subsp. nipponica produced Armillaria rhizomorphs on PDA and PCDA. Armillaria gallica, however, formed no rhizomorphs on MDA, YDA, PDA and PCDA. All Armillaria species, except A. gallica, showed extra mycelial growth and rhizomorph formation on SRB (sawdust-rice bran) from broad-leaved trees. Mycelial growth and rhizomorph formation of all species were promoted on L. kaempferi SRB. Their rhizomorph formation on A. sachalinensis SRB and P. jezoensis SRB were inhib­ ited. Mycelial growth and rhizomorph formation were promoted for all species on BMDA (bark extract-MDA), except A.ostoyae and A. gallica on B. Platyphylla var. japonica BMDA. Armillaria gallica, which did not form rhizomorphs on other media, showed the promotion of rhizomorphs on BMDA of coniferous trees. Armillaria species which two new species, A. jezoensis and A. singula, and a new subspecies, A. mellea subsp. nipponica, from Hokkaido showed better mycelial growth and rhizomorph formation than other species on medium amended with bark extract and sawdust from local trees.