300 The Spraying of Plants. 



injury to the appearance of the fruit, so much the better. It 

 is necessary that the growth from the spores which fall upon 

 the berries should be stopped, and this can only be accomplished 

 by treating the clusters, as well as the other parts of the vine. 



The cost of spraying grape-vines depends upon a great many 

 factors, all of which cannot here be discussed in detail. Good 

 machinery is of the greatest importance, for upon this depends 

 the quality of the spray. Reliable help will also increase the 

 cost of the work, for such men will use more time and more 

 material than shiftless workers. Yet only such labour should 

 be employed. The time of the year also affects the cost of the 

 work, since early in the year there is much less surface to be 

 covered. The character of the season also influences the total 

 outlay of the year, for in some seasons twice as many appli- 

 cations may be required as during others. A few data regard- 

 ing the spraying of grapes may be mentioned, with the assurance 

 that they will serve as guides to those beginning the work. 



Taking an average of the applications made during the entire 

 season, it may be said that each vine should receive approxi-. 

 mately one quart of liquid at each application. The cost of 

 material and labor should not much exceed one-half a cent per 

 vine for each treatment, whether the Bordeaux mixture or the 

 ammoniacal carbonate of copper is used, the latter being a little 

 more expensive. When this small outlay is compared with 

 the great benefits which so commonly result from the work, it 

 is strange that the practice is not more generally followed. The 

 above figures refer to vines of the Concord type, these making 

 a very extensive growth. For less vigorous varieties the cost 

 may be reduced, and the use of some of the machines now 

 manufactured will still further lessen the expense. This is 

 especially true in the North, where the black rot and other 

 fungous diseases of the grape are not so serious as southward. 



Downy Mildew; Brown Rot; Gray Rot (Peronospora viticola, 

 DeBary). Description. This fungus attacks the steins, foli- 

 age, and fruit of the grape-vine. While it is not generally so 

 serious as the black rot, in the northern states it is more com- 

 monly seen, and probably causes the loss of more grapes than 

 its southern neighbor. 



The external characters of the downy mildew are very dis- 

 tinct. On the shoots it causes the formation of brown, slightly 



