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A NEW DISEASE OF THE HOP-VINE CAUSED BY 

 PERONOPLASMOPARA HUMULl N. SP. 



Bv 



KlXGO MlYAEE, SD.. Rigakuhakuslii. 

 Professor of Botany in the Sapporo Agriccltural College. LIBRARY 



NEW YOf»K 



BOTaMc'v 



AND 



YOSHIXAO Takahashi, Nogakushi. 



Botanist to the Hokkaido Agricultural Experiment Station, Sapprr:. 



It was in the early summer of 1905 that our attention was first drawn to a 

 diseased appearance of the leaves of the cultivated hop- vines in the experimental 

 plat of the Hokkaido Agricultural Experiment Station in Sapporo. An examina- 

 tion shov\ed at once that it was due to a kind of downy mildew, having a close 

 affinity to that of cucumber. Our interest was naturally aroused leading us to 

 inquire into the extent of the damage done in other hop fields about Sapporo, and 

 also into its occurrence on the wild hop, which is not uncommon in this vicinitj- 

 as well as in other districts in northern Japan. 



In the hoj>-field belonging to the Sapporo Brewer\- Company a careful search 



was made on June 1 5th this year, and we found the mildew to have already begun 



^ to spread to an alarming extent throughout the field. A portion of the field 



'—' adjoining the place where the hop-vines were collected and burnt the previous 



»^ 



gsQ autumn was ver>' badly attacked. The lower leaves of the vine were at that time 



— ' most infected, but the disease had already spread to some of the upper leaves. 



~Z Judging from the extent to which the fungus had spread in the field, we may safely 



infer, that the disease had existed there for many years without drawing attention. 



[Tran?. Sap. Xat. Hist. Soc, V. 1. T. Part 2] 



