U. S. EXPERIMENT STATION BULLETINS. 



421 



The analyses of such vegetables show that they contain copper in con- 

 siderable quantity, as will be seen by consulting the table below: 



Table showing copper in 1 kilogram of re-greened canned vegetables. 



It appears from the foregoing that vegetables re-greened by the copper 

 process may contain from two to sixty times as much of the metal as 

 sprayed grapes. In other words, if 1,000,000 pounds of sprayed grapes 

 contain 5 pounds of copper, 1,000,000 pounds of re-greened vegetables 

 would contain from 38 to 150 pounds of the metal. Great Britain imported 

 over 14,000,000 pounds of canned vegetables from France in 1890, and it is 

 safe to say that these vegetables contained more than twenty times as much 

 copper as all the sprayed fruit in the United States combined. 



FUNGOUS DISEASES OF 



THE GRAPE AND THEIR TREAT- 

 MENT. 



GRAPE DISEASES. 



There are but four fungous diseases of the grape in this country which 

 occasion sufficient damage to warrant our attention in this bulletin. 

 They are : ( 1 ) The grape peronospora or downy mildew ; ( 2 ) powdery 

 mildew; (3) black rot, and (4) anthracnose. These we shall endeavor 

 to describe in such a way that any one not familiar with them may be 

 able to recognize them and act accordingly. 



Grape peronospora or downy mildew, brown rot, and gray rot. — The 

 fungus causing these diseases is known to botanists as Peronospora vit- 

 icola. It attacks the leaves, young wood, flowers, and fruit. On the 

 leaves it usually manifests itself first in the form of greenish yellow or 

 brownish spots on the upper surface, while on the lower side corre- 

 sponding parts are covered with a white frost-like growth. As the dis- 

 ease progresses the frost-like patches may disappear, leaving only the 

 brown leaf, which soon dries up and falls off. Young wood and flowers 

 are affected in much the same way, but owing to their structure the 

 downy or frost-like stage is more pronounced. This form of the disease 

 is known as the downy mildew, and in some sections it causes the only 

 serious damage. On the fruit the fungus occurs in two forms, causing 

 what is known as brown and gray rot. The former disease as a rule does 



