New Yokk Agricultural Experiment Station. 245 



they might have covered the same period; but it is deemed 

 unnecessary to continue them further. 



Like the ten-year experiments the business experiments have 

 shown widely varying results in ditierent localities. As a rule, 

 spraying has been more profitable on damp, loam soils than on 

 dry, sandy soils ; and better results have been obtained in sheltered 

 than in exposed situations. Also, the fertility of the land and the 

 variety of potato are factors. Most important of all is the thor- 

 oughness of spraying. 



Some of the experiments have been conducted quite carefully 

 and others carelessly. In several cases there have occurred puz- 

 zling differences in yield which were probably due to some other 

 cause than spraying. Although care has been taken in the location 

 of the test rows soil differences have often been a disturbing factor. 

 Sometimes the expense accounts have not been kept properly. In 

 short, the manner in which the experiments have been conducted 

 is far fix)m satisfactory. Nevertheless, it is believed that the 

 results obtained show, approximately, the profit from spraying as 

 practiced by the better class of potato growers in New York. That 

 spraying is profitable there can no longer be any doubt. Even 

 if we make the generous allowances of 30 per ct. for errors there 

 remains an average net profit of $10 per acre. Moreover, there 

 is good reason to believe that the average net profit would have 

 been considerably larger had the spraying been properly done in 

 all of the experiments. In most cases the spraying was not suffi- 

 ciently thorough. Evidence of this is seen in the results of double- 

 spraying as compared with single-spraying. 



The writers hold that these experiments have given a very 

 definite answer to the question, Does it pay to spray potatoes? 

 The spraying of late potatoes in New York is highly profitable. 

 No one who grows potatoes extensively can afford to neglect 

 spraying. 



SINGLE- VERSUS DOUBLE^SPRAYING. 



Observations on the farmers' business experiments led us to 

 suspect that, in most cases, the spraying was not done thoroughly 



