57 



begin his treatments early — in advance of the fungus in fact — and r©» 

 peat them often enough to keep his vines and the fruit thoroughly pro- 

 tected until harvest. 



Assuming that our grape-grower is in possession of these facts, his 

 first step will be to provide himself with suitable apparatus for the work 

 in hand. If he has a small vineyard of 5 or 6 acres, a hand machine 

 in the shape of a knapsack pump will in all probability be used. Such 

 a machine may now be procured for a few dollars, and with it a vine- 

 yard of 5 or 6 acres can be thoroughly sprayed in a day and a half. 

 The question of a machine being settled, the fungicide or solution to be 

 used is the next important matter to consider. If thoroughly posted, 

 he will be aware that of the numerous preparations used only three or 

 four can be relied on at all times. One of these he decides upon, so 

 there is nothing further to do but to lay in his stock of chemicals, and 

 wait until the toliage is about half grown, or say 10 or J.2 days before 

 the vines blossom. The chemicals needed for his work are strong aqua 

 ammonia and carbonate of copper, the latter being a fine bluish-green 

 powder which may be obtained from almost iiuj drug stoie. The proper 

 time having arrived for making the first spraying, the chemicals, 

 together with two or three barrels of water, the spraying machine, etc-t 

 are taken into the field. Five ounces of the carbonate of co[)per arc 

 then weighed out and dissolved in three pints of ammonia. This solu- 

 tion is poured into a barrel of water and is then ready to be applied. 

 The pump is now brought into play, the reservoir being first filled and 

 then taken upon the back, knapsack fashion. By means of the right 

 hand the pump is worked bellows fashion, over the right shoulder. 

 This forces the liquid out through the hose and nozzle on the left side- 

 The nozzle is, therefore, placed in the left hand, and by means of it the 

 spray is directed over the vine. The entire cost of treating an acre as 

 here described will not exceed one dollar. About the time the berries 

 are forming another spraying should be made and this should be re- 

 peated every twelve or fourteen days until five or six applications, cost- 

 ing about one dollar each, have been put on. If the work has beea 

 carefully done, comparatively few berries will rot, and this in badly- 

 infected regions means a profit of from 200 to 400 per cent, on the 

 amount expended in the work of spraying. This is only one example 

 of how the fight is made against foes of this kind. Of course the 

 methed will vary somewhat with each disease. It will be seen, we be- 

 lieve, that the laborator}' work plays an important part in every step 

 taken in the field. It is this work that has taught us the habits of the 

 fungus, the time to make the treatments, and the physiological efi^ects 

 of these on both fungus and host. 



Brief reference has already been made to some of the practical 

 results of this work. To bring out this matter more clearly, however^ 

 we will cite a few facts bearing on this subject which have accumulated 

 within the past two years. In the past there has been a tendency ta 

 belittle the scientific work of the Department of Agriculture, especially 

 in its beai ing upon practical farming and fruit growing. It is ofteiL 

 claimed that much of the money expended by this branch of the Gov- 

 ernment does little toward advancing the cause of the tiller of the soiL 

 Let us then look at this matter of investigating plant diseases from a 



