APH 29 1924 
ON A NEW CANKER-DISEASE OF 
PRUNUS YEDOENSIS, P. MUME AND 
OTHER SPECIES CAUSED BY 
VALSA JAPONICA MIYABE et HEMMI sp. n. 
BY 
Takewo Hemmi, Nogakushi 
(With Plates VII-X) 
1. Introduction. 
The canker-disease of Prunus yedoensis Matsum. (Somei-yoshitio) was 
first noticed in 191 3 by Prof. K. Mivabe in the Botanic Garden of our Univer- 
sity, and was proved by him to be due to a species of Valsa. It was in the 
early spring of 19 14, that my attention was drawn to the seriousness and 
widespread occurrence of the disease in the vicinity of Sapporo, when, at the 
suggestion of Prof. K. Miyabe I resolved to undertake the investigation of the 
disease. Since that time, many samples of the diseased branches and stem 
have been collected on different species and varieties of Prunus. Among 
those affected by the disease, Prunus Mumc S. et Z. seems to be very suscep- 
tible to the disease, and its causal fungus was proved to be the same as that 
of Prunus yedoensis by my cultural and inoculation experiments. The peach 
tree {Prunus Persica S. et Z.) was also proved to be sometimes attacked by 
the same fungus, but the extent of its damage was not investigated in my 
study. According to my observations, Prunus sachalincnsis Koidz. (Oyama- 
zakura or Yezo-no-yamasakura) seems to have a strong resistance against the 
disease, though not immune. As to the other host plants my observations 
and studies are not yet complete, and I wish to defer their report to a future 
occasion. The fact that the canker disease has not yet been found oh the 
European Cherry tree {Prunus Ccrasus L.) in the vicinity of Sapporo, notwith- 
[Jour. of the College of Agr., Tohoku Imp. Univ., Sapporo, Vol. VII, Pt. 4, August, 1916] 
