STRAWBERRY DISEASES 425 



Trelease, William. The spot disease of strawberry leaves. Wisconsin 



Agr. Exp. Sta. Kept. 2 : 47-58. 1885. 

 Halsted, B. D. The strawberry leaf spot. New Jersey Agr. Exp Sta 



Kept. 1893 : 328-329. 1894. 

 Bailey, L. H. Varieties and leaf blight of the strawberry. Cornell 



Univ. Agr. Exp. Sta. Bui. 79 : 583-604. 1894. 

 Garman, H. Some strawberry pests. The strawberry leaf-blight 



fungus. Kentucky Agr. Exp. Sta. Bui. 31 : 3-13. 1890. 

 Jackson, H. S. Strawberry diseases. Leaf spot. Oregon Crop Pest 



and Hort. Bienn. Kept. 1911-1912 : 268-269. 1913. 

 Wolf, F. A. Strawberry leaf blight. Alabama State Hort. Soc. 



Proc. 11 : 56-58. 1914. 



POWDERY-MILDEW 

 Caused by Sphcerotheca Humuli (Fries) Burr. 



Strawberry powdery-mildew was first reported from Eng- 

 land in 1854, at which time it was of considerable impor- 

 tance. In 1885 it again became noticeable in England. The 

 next year it was found in America (New York State). In 

 1892 it was recorded from Massachusetts, but prior to 1896 

 the disease was rarely serious in the United States. Now the 

 disease is common and widespread and is capable of doing 

 serious damage. 



Sometimes all varieties are affected ; again certain ones are 

 immune. Among the susceptible varieties may be noted : 

 Paxton, British Queen, Black Prince, Jucunda, Mount Vernon, 

 May King and Garrettson. On the other hand, the Noble and 

 Royal Sovereign are said to be resistant. 



Symptoms. 



In the first stages the leaves are affected. They curl at the 

 margin and thus expose their lower surfaces. Affected plants 

 present an appearance as in need of water. Powdery, white 

 growth of the mildew-pathogene appears on the lower surface. 

 This is frosty and mealy in aspect. Berries are affected in 

 all stages of development. They are rendered tasteless and 



