Ecology of pitaya stem rot caused by Gilbertella persicaria and its biological control by phyllosphere bacteria

Abstract

Pitaya is a succulent plant native to Central American countries, such as Mexico, and belongs to the Cactaceae family. It is cultivated in many countries, including Israel, Japan, Taiwan, and Vietnam (Yonemoto, 2009). It has been cultivated in the Okinawa Prefecture since the late 1980s and is now grown in Kagoshima and Miyazaki (Yonemoto, 2009). In Okinawa, mainly white (Hylocereus undatus), red (H. polyrhizus), yellow (Selenicereus megalanthus), and pink (H. undatus × H. ocaponis) pitaya plants are cultivated.Pitaya can be easily cultivated in the open air and remains relatively disease-free. However, recently, successive disease outbreaks such as mosaic (Natsuaki & Shinkai, 2001), anthracnose (Taba et al., 2003, Rhizopus rot (Taba et al., 2006), fruit rot (Taba et al., 2007, and Gilbertella stem rot (Taba et al., 2011) have been reported. In particular, stem rot is a considerable problem, which not only causes softening and rotting of the stem nodules but also causes poor fruiting and postharvest damage.Generally, plant diseases are managed and controlled by using chemical substances. However, in Japan, where chemical control