SPRAYING 323 



mildew is a fungous disease causing brownish white patches 

 on the under surface of the leaves. It sometimes attacks 

 the fruit as does the black rot, but the infected fruit turns 

 red rather than black. Delaware and other hybrid varie- 

 ties are most susceptible to the mildew. The powdery 

 mildew is most common in hot, dry weather, covering the 

 surfaces of the leaves or fruit and giving them a gray or 

 powdery appearance. 



The phylloxera, or root louse, is not a serious insect on 

 the American varieties, but upon the European varieties 

 it is one of the most dreaded and destructive of all insects. 

 Grafting these varieties on our native stocks is the best 

 preventive. Sometimes the grape cane borer proves very 

 destructive, attacking the young shoots in the spring and 

 causing them to droop suddenly or break off entirely. To 

 control this insect, all diseased wood and prunings should 

 be promptly burned. Injured shoots should also be cut 

 off and burned at once. The rose chafer and leaf hopper 

 are the most difficult insects to control upon the grape. 

 Spraying with tobacco extracts is probably the most effi- 

 cacious remedy. Clean cultivation and the destruction of 

 all leaves, grass, and other debris in the neighborhood that 

 might make a harboring place over winter for these insects 

 will help to prevent them. The leaf hopper feeds early in the 

 season upon the strawberry and bush fruits, hence these 

 fruits should be grown some distance from the vineyard. 



Spraying. If fruit free from rot, mildew, and other 

 fungous diseases is desired, spraying must be practiced 

 regularly. When the shoots are from eight to ten inches 

 long the vines should be sprayed with Bordeaux mixture 

 to prevent the black rot and downy mildew. The vines 

 should be sprayed again, just before the blossoms open, with 



