Abstract
An unknown stem rot of pitaya (H. undatus; Cactaceae) was observed in orchards in Okinawa, Japan in 2005. A Gilbertella species was isolated from diseased stems, and typical symptoms were reproduced after inoculating wounded stems with isolates. The causal fungus was identified as G. persicaria (Eddy) Hesseltine on the basis of morphological characteristics, growth and germination temperature, and rDNA-ITS sequence homology. The name Gilbertella stem rot (Kukigusare byo) was proposed for this new disease.
