4 U.S. DEPT. OF AGRICULTURE MISC. PUB. 9 39 



Person in charge. — Prof. N. Hiratsuka, Tokyo University of Edu- 

 cation. 



Pathologists. — Prof. N. Hiratsuka, ex-Prof. Senji Kamei, Hok- 

 kaido Universit}^; Prof. Nobukiyo Takahashi, Tokyo University; 

 Asst. Prof. Katsuya Nakamura, Tokyo University of Agriculture and 

 Technology; Prof. Shigeyasu Akai, Kyoto University; Prof. Iwao 

 Hino, Yamaguchi University; Dr. Yoshikazu Nishikado, Director, 

 the Nishikado Mycological Institute, formerly Prof, of Okayama 

 University. 



Entomologists. — Prof. Toichi Uchida, Hokkaido University; Prof. 

 Masatoshi Nittoh, Tokyo University; Dr. Yoshihiko Kurosawa, Cu- 

 rator, National Science Museum ; Prof. Teiichi Okutani, Hyogo Agri- 

 cultural College; Asst. Prof. Magoshiro Moritsu, Yamaguchi 

 University. 



At the start of this research, we focused our attention on the follow- 

 ing kinds of trees as the main objects for the investigation: Acacia 

 dealbata and A. mollissima, Eucalyptus robusta and E. globulus, Popu- 

 lous spp.. Larix europaea and L. dahurica, Picea excelsa, and Pinus spp. 

 (banksiana, elliottii, koraiensis, palustris, radiata, rigida, strobus, 

 sylvestris, and taeda). 



The researchers have made steady progress during the past 2 

 years. Recently, Prof. N. Hiratsuka presented an intermediate report 

 of the results obtained in 1959 to the Forestry Agency. According to 

 this report, the research members collected 475 specimens of diseases 

 and 355 specimens of injurious insects from various regions. The 

 identifications are not yet completed. 



While this joint research was being carried on, the forest patholo- 

 gists and entomologists in the Government Forest Experiment Station 

 were also working on the same studies in cooperation with the joint 

 research group. Annually a meeting has been held to discuss the re- 

 sults obtained and to facilitate further studies on them. 



From these investigations, it became clear that we must pay more 

 careful attention to the following diseases. 



Poplar diseases. Dieback of poplars caused by Diaporthe medusae 

 Nit. prevails in Honsyu, the middle part of Japan. Dieback and 

 canker caused by Cytospora chrysosperm,a and Leucostoma nivea oc- 

 curs in Hokkaido, the northern region of Japan. Among five kinds of 

 rust diseases, leaf rust caused by Melampsora larici-populina, Kleb. 

 is the most common and serious. Marssonia brunnea (E. & Ev.) 

 Magn. attacks leaves and young shoots. Poplars belonging to the sec- 

 tions Aigeros and Tacamahaca are severely damaged. Septotis popu- 

 liperda (Moesz & Smarods) Wat. & Cash which causes the leaf blotch 

 is believed to have been introduced with cuttings imported from 

 abroad. 



Acacia diseases. Glomerella (Physalospora) acaciae Ito & Shibu- 

 kawa causes very severe damage to nursery stock. 



Eucalyptus diseases. Damping-off caused by Pythium, Fusarium, 

 Rhizoctonia, and Cylindrocladium are very severe. 



Larch diseases. Shoot blight caused by Physalospora laricina Sa- 

 wada is very dangerous in northern regions of Japan. I shall report 

 further on this disease later on. Larix europaea and L. dahurica are 

 very susceptible. 



Pine diseases. Pinus sylvestris is very susceptible to Oronartium 

 quercuum. Young plantations of P. strobus are sometimes attacked 



