194 HARUYOSHI SAHO 



Hokkaido University, and supported by five Hokkaido National Forests 

 reinvestigated Dr. Togashi's alarming report. They confirmed and reported 

 (Kamei, Igarashi, Saho, et al. , (1958) that the rust on R. latifoliwn on 

 Rebun Island indeed appeared to be C. ribicola; more important, they also 

 reported the rust present on R. latifoliwn at Meiji Nursery, Kitami 

 National Forest in northwest Hokkaido. 



Then, in 1959, an IUFRO Working Group concerned with internationally 

 dangerous forest tree diseases, headed by Prof. N. Hiratsuka of Tokyo 

 University of Education and including pathologists from the Government 

 Forest Experiment Stations and universities, continued the search for 

 C. ribicola. Again a rust, morphologically very similar to C. ribicola, 

 was collected on Ribes in several parts of Hokkaido (Imazeki, 1963). 



Finally, in 1963, a rust similar to C. ribicola was found on the 

 campus of Hokkaido University on Ribes rubrum L., this Ribes species 

 having been introduced 60 years ago into Japan. Immediately (September 16) 

 Dr. Kamei and his Colleague Dr. T. Igarashi commenced inoculation experi- 

 ments (Kamei and Igarashi, 1963), using seedlings of P. strobus and P. 

 koraiensis. Yellow needle spots appeared on the needles of both pines, 

 in the greenhouse 18 to 39 days after inoculation. Three years later a 

 typical spindle-shaped, discolored stem canker with resin flow was found 

 on the inoculated portion of one P. koraiensis seedling, but up to 1968 

 no pycnia or aecia of the rust have appeared. Stems of all of the inocu- 

 lated P. strobus seedlings remained healthy. 



Thus despite all this concerted action toward verification of the 

 presence of C. ribicola its presence in Japan remains conjectural. 



It is most interesting that in Korea they find a rust similar to C. 

 r-lbicola on P. koraiensis 3 in the absence of Ribes spp. (but not on P. 

 strobus despite presence of rust-infected Ribes 3 see Bakshi, these 

 proceedings). 3 Meanwhile in Japan we may have been able to inoculate P. 

 koraiensis needles and stems with this "C. ribicola-like rust" from Ribes 

 but not induce other than needle spots on P. strobus. 



VOLE AND HARE DAMAGE TO WHITE PINES 



Takahashi and Nishiguchi (1966) made laboratory tests of vole gnawing 

 damage. In these tests, P. griffithii proved to be the most attractive 

 to the red-backed vole--bark gnawing was severe. , P. strobus and P. monticol 

 were the next most severely gnawed, while P. koraiensis and P. pentaphylla 

 were found to be rather unattractive (i.e., resistant to vole gnawing). 



Earlier Takahashi and Iwamoto (1963) reported on rodent damage in the 

 field. Seedlings of several species of conifers and broadleaved trees 

 that were planted in a test area. Rodent damage was observed the next 

 spring. Under snow cover, the bark of all but two species was gnawed by 

 the red-backed vole. Moreover, the tops of all but 3 seedlings above the 

 snow cover were gnawed by hares. The results of the field observation are 



3 Editor's note: It has come to our attention quite recently that 

 pathologists of the Korean Forest Research Institute near Seoul so far 

 have unsuccessfully attempted inoculation of R. mandshuricum var. villosum 

 Kom. with aeciospores similar to those of C. ribicola from the Korean 

 P. koraiensis blister rust. 



