New York Agricultural Experiment Station. 387 



Even if the comparison is made with |4, the total expense of 

 spraying, there will still be a profit on all the varieties except 

 Victor Rose— 12.81 loss on Victor Rose, |11.14 profit on White 

 Elephant, |11.52 profit on Green Mountain and 2 cents profit on 

 Defender. 



The results of this experiment tend to show that it will pay to 

 •pray potatoes on Long Island every season; for if it has been 

 profitable the past season it will be profitable any season. The 

 season of 1896 was certainly an unusually favorable one for 

 potatoes on Long Island. It is rare that potato plants are s© 

 generally free from the various blights. 



THE REQUISITES OF A POTATO SPRAYING EXPERI- 

 MENT. 



The spraying of potatoes has never been practiced to any great 

 extent on Long Island. Last year several farmers tried it for 

 the first time and on account of the lack of blight they failed to 

 obtain the striking results which they had expected. They saw 

 no marked contrast between their fields which had been sprayed 

 and their neighbors' fields which had not been sprayed. In some 

 cases the unsprayed fields made the better appearance. Some of 

 the more careful ones took the precaution to leave an unsprayed 

 strip through the center or along one side of the sprayed field in 

 order to make the test a fair one. They who did this must have 

 observed a difference between the sprayed and unsprayed plants, 

 but probably considered the difference so slight as to be of no 

 practical importance. Had they completed the experiment by 

 carefully measuring the land and measuring the potatoes on the 

 sprayed and unsprayed portions of the field they would, most 

 likely, have been astonished. A difference of from 15 to 20 

 bushels per acre can scarcely be detected while the crop is grow- 

 ing or even after the tubers have been thrown out by the potato 

 digger, and yet this quantity is ordinarily sufiBcient to pay the 

 expense of spraying. 



To those persons who doubt that spraying pays, we suggest 

 that they give it a fair test. A fair test requires that care be 

 taken to avoid all unnecessary expense and that the sprayed and 

 mnsprayed plants shall be under practically the same conditions. 



