GOOSEBERRY-MILDEWS 109 



GOOSEBERRY-MILDEWS 

 By JAMES W. H. TRAIL, A.M., M.D., F.R.S. 



TllE leaves of Gooseberries have long been known to be 

 liable to the attack of a mildew, which covers them with a 

 thin pale grey web of slender interwoven tubular cells, which 

 draw their nourishment from the leaf by means of suckers 

 pushed into the cells of the surface on which they grow. 

 On the web after a time appear small balls, changing from 

 yellow to dark brown. Each of these bears around it a 

 circle of from 10 to 15 appendages as long as the diameter 

 of the ball, in the form of stiff brown tubular cells, which 

 end in repeatedly bifurcated pale tips imbedded among the 

 web. The balls inclose in each from 4 to 8 asci, each con- 

 taining about 4 ascospores. This fungus, Microsphcera 

 Grossularia, Lev., has been found throughout Europe, in 

 Northern Asia and in North America, and in colonies else- 

 where, to which it has been carried. It is often exceedingly 

 prevalent, especially in autumn. It has* been recorded from 

 many localities in Scotland, in all parts of the country. 

 But though so common, and certainly weakening the plants 

 to some extent, it does not appear to injure the fruit to any 

 serious extent. But since 1834 another mildew has been 

 observed in North America on the fruits of various species of 

 Ribes, and is known by the name of SpJicerotheca Mors-uvce 

 (Schw.) Berk. Originally found on R. Uva-crispa, it has since 

 been found on several other species, including the gooseberry. 

 It has extended its range widely in the United States and 

 in Canada, and is dreaded as a dangerous scourge of the 

 gooseberry. In 1900 it was observed, for the first time to 

 the east of the Atlantic Ocean, in three gardens in the north- 

 east of Ireland. Attention was called to its occurrence there, 

 and to the danger of its becoming epidemic in Europe, by 

 Mr. E. S. Salmon, F.L.S, in the "Journal of the Royal Horti- 

 cultural Society," a full description and figures being given to 

 allow of the recognition of the fungus and the destruction of 

 infected bushes with the least possible delay. 



It was found in central Russia in 1901, on bushes sent 

 from St. Petersburg and Riga two years previously. In 



