GOOSEBERRY-MILDEW AND GOOSEBERRY CULTIVATION. 469 



GOOSEBERRY-MILDEW AND GOOSEBERRY CULTIVATION. 



The Peesent Aspect of the Question. 



By Professor Jakob Ekiksson, Ph.D., Hon. F.R.H.S., 

 of the Experimentalfultet, Stockholm as on p. 472. 



1. The Native Country of the Fungus. — The American gooseberry- 

 mildew (Sphaerotheca mors-uvae, Berk.) is a native of North America 

 where it has been known at least seventy years. It has ruined partially 

 or entirely the cultivation of gooseberries in North America, especially 

 of the European varieties, which are improved descendants of the species 

 Bibes Grossularia. 



2. The Immigration and the Spread of the Disease in Europe. — The 

 disease has spread in Europe from two centres, one in the east and one 

 in the west. 



From tfre eastern centre the spread seems to have commenced about 

 the year 1890, or a year or two earlier. The disease was then introduced 

 into a garden in Winnitzy, in Podolia (South-West Russia), by means 

 of directly imported American gooseberry-bushes. In 1890 it appeared 

 in the town of Winnitzy and its neighbourhood. Thence it spread to 

 the Government of Moskva and to the Baltic Provinces. In the year 

 1904 the disease had become established in European Russia in ten 

 widely separated localities, and subsequently it has spread from Russia 

 to the neighbouring European countries. 



From the western centre the disease began to spread about ten years 

 later, viz. in 1900, when it was introduced simultaneously into Ireland 

 and into Denmark. Since then it has spread from these places to other 

 States of North-Western and North Europe. 



At the present moment we may mention as the most affected countries 

 of Europe — Russia, Finland, North-East Germany, Ireland, Denmark, 

 Sweden, and Norway. 



3. The Intensity of the Disease. — Since its introduction into Europe 

 the disease has increased in virulence, and there are no signs at all that 

 indicate any weakening of the fungus. 



4. The Sttsceptibility of Different Varieties of Gooseberry. — No differ- 

 ence of susceptibility between different varieties of gooseberry has yet been 

 noticed sufficient to afford ground for believing that the disease can be 

 fought by means of resistant varieties. 



5. The Disease Attacking other Species of Plants.— The fungus 

 has also been observed in some localities on Bibes nigrum, B. rubrum, 

 B. aureum, &c, but, so far as I know, in no place very abundantly. In 

 one place of South Sweden the fungus appeared on Bubus Idaeus in two 

 consecutive years. 



6. The Outbreak of the Disease. — In many cases we can distinguish 

 between the spring, summer, and autumn outbreaks. 



The spring outbreak — occurring at Stockholm from the middle to the 



