Current Status and Issues of Research on Passalora Needle Blight Disease of Japanese Cedar

Abstract

Passalora needle blight caused by Passalora sequaoiae is one of the serious disease in the nursery of Japanese cedar (Cryptomeria japonica). It was epidemic in the early 1900s and during the period of expansion reforestation in the around 1950, and caused devastating damage to nursery production of Japanese cedar. At present, the damage of this disease has not become a serious problem, but this disease is by no means a past disease. If it is not properly controlled, it still causes damage to nursery of Japanese cedar. Whereas, it is also true that with accurate knowledge on this disease, the damage caused by this disease could be almost completely controlled. With the recent increase in production of cedar saplings for re-afforestation, it is concerned that this disease will be prevail. The damage of this disease has already occurred in several areas, and this may also occur in containerized seedlings recently developed in Japan. The purpose of this review is to compile the knowledge of this disease that is likely to be damaged again in the near future, to understand of this disease, and to organize the further issues.