1'2 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Known in Europe — in France, Germany, and Italy — as well as in the 

 United States. 



U.S.A. Exp. Sta. Cornell, xiv. Dec. 1889 ; Sacc. Syll. i. 1951 ; Mass. 

 PI Dit. 107, fig. 18 ; Tubeuf, Dis. 215, fig. 



Strawberry Mildew . 



Sphcerotheca liumuli (DC). 



A white mould on Strawberries was recognised by Berkeley in 1854, 

 when he imagined it was the same species as had been known on Turnips. 

 Afterwards the occurrence of the same mildew in America led to its 

 further investigation, t and it was discovered at length to be none other 



and spores. ( x 350.) 



than a form of the well-known mildew of the Hop. In this country only 

 the fonidial condition had been seen, which was a simple Oidium, some- 

 what like that of the Vine. On the other hand the perfect fruit was 

 found in America, bo that between 1892 and 1898 it became established 

 that the fungus of the Strawberry mildew was that known as Sphmrotheea 

 humuU (or, afl formerly termed, Sphcerothcca Castcujuei), the cause of the 

 I tap mildew. | Pig, 10.) 



In the first stage it attacks the leaves, causing them to curl, so as to 

 ;i].|..ar us if siift4Tiii.LT for lack of water. At this time the mycelium 

 pn ftdl inner the nnder surface as a white felted mould, from which arise 

 kh< ho. t branches w hich bear the chains of conidia (30-35 x 20-21 /*). 



