Rhizoctonia solani AG-2-2ⅢB によるミツバ立枯病

抄録

Damping-off of Japanese hornwort（Cryptotaenia japonica）was found in Hokkaido, Japan in July 2007. A Rhizoctonia-like fungus was frequently isolated from the diseased portion of the plant. We identified this isolate as Rhizoctonia solani anastomosis group（AG）-2-2ⅢB on the basis of cultural morphology,mycelial growth at different temperatures, hyphal anastomosis, and the result of PCR using subgroup-specific primers. An inoculation test with the isolate revealed that the fungus caused the same symptom on Japanese hornwort and was reisolated from the portion of the plant exhibiting the symptom. Because it has not been reported as a pathogen causing damping-off of Japanese hornwort in Japan, except for R. solani AG-1ⅠB and AG-4HG-Ⅰ, we propose R. solani AG-2-2ⅢB as a new pathogen of Japanese hornwort.