Trunk sap rot of Japanese cedar (Cryptomeria japonica) caused by Fomitiporella sinica

ABSTRACT

Trunk rot caused by the wood decay fungus Fomitiporia torreyae is a serious disease of Japanese cedar. The rot is characterized by white sap rot with brown zone lines and vertical depressions on the trunk. During our field investigations on this disease, we found another sap rot on Japanese cedar, characterized by white rot with brown zone lines, with or without less obvious depressions on the trunk. The results of phylogenetic analysis of the most frequently isolated fungus from the diseased trees and morphological observation of basidiocarps previously identified as Fomitiporella umbrinella showed that both represented Fomitiporella sinica. Our inoculation tests using Japanese cedar showed that F. sinica caused longer discoloration in sapwood compared with control treatment. Therefore, we concluded that F. sinica was the cause of trunk rot on Japanese cedar as reported for F. torreyae, but trunk depressions were not obvious in the trees infected with F. sinica. Moreover, branch scars were found around the middle of decaying parts of diseased trees infected with F. sinica, and infection with this fungus was assumed to occur via dead branches or pruning scars.

KEYWORDS:

• Decay disease
• Fomitiporella umbrinella
• Fomitiporia torreyae
• wood decay

Acknowledgments

We thank Prof. Y.C. Dai of Institute of Microbiology, Beijing Forestry University for the loan of the holotype of F. sinica. We are grateful to Mr. Satoshi Tsujimoto of Okinawa Churashima Foundation for providing samples and the staff of Research Coordination Office of Kansai Research Center, Forestry and Forest Product Research Institute, for their help during sampling. We also thank Ms. Kazuko Komaru and Atsuko Matsumoto of Forestry and Forest Product Research Institute for their assistance with the molecular experiments.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported in part by research grants from the Forestry and Forest Products Research Institute, Tsukuba, Ibaraki Prefecture, Japan [#201708 and #202005].