First report of root and stem rot of sedum caused by five oomycete species

Root and stem rots of sedum were observed in Japan. Five representative isolates that caused similar symptoms were identified as Phytopythium helicoides , Phytopythium vexans , Pythium myriotylum , Globisporangium irregulare , and Globisporangium ultimum based on morphological characteristics and DNA sequence data. Phytopythium helicoides, P . myriotylum and G . ultimum were highly virulent to sedum; the others were moderately virulent. Root and stem rots of sedum caused by oomycete species have never been reported in Japan. We propose that this new disease of sedum be named “ negusare byo ” in Japanese.