New York Agricultural Experiment Station. 143 



The cost of spraying per acre, for each appHcation, was 80 cents. 



Since the increase in yield was at the rate of 64 bushels per acre, 

 the total gain due to spraying 14 acres must have been about 896 

 bushels of potatoes worth $448. Deducting from this sum the ex- 

 pense of spraying, $55.76, there is left $392.24 which is the net profit 

 on 14 acres. This is at the rate of $28.01 per acre. 



From the first of September on, these two Salisbury experiments 

 were visited by the writers every three or four days and full notes 

 on them taken. We regard these .experiments as the most instruc- 

 tive ones of the whole series. The conditions under which they were 

 made are fairly representative of the conditions prevailing in the 

 potato growing sections of central and western New York. The 

 yield, 92 and 83 bushels per acre (for the unsprayed rows), are 

 average yields. The sprayer used is one which is upon the market 

 and can be operated by any man of average intelligence. The rate 

 of increase in yield was determined in such a manner that there can 

 be no doubt as to its accuracy and there is good reason to believe 

 that the same rate prevailed througout the whole field in both experi- 

 ments. The writers, themselves, measured the test rows and super- 

 intended the digging and weighing. Mr. Salisbury's statement of 

 the amount of the expense of the spraying is, likewise, to be relied 

 upon. If it is thought that any proof is needed it is found in the 

 fact that he sprayed potatoes for some of his neighbors at 80 cents 

 per acre and furnished everything. 



THE WELCH EXPERIMENT. 



This experiment was made by Ed. Welch, Phelps, N. Y. A field 

 of 33/2 acres of potatoes was sprayed five times with an old two-horse, 

 six-row power sprayer of the same make as that used in the Salis- 

 bury experiments. It was bought second hand in 1902 for $10. 

 One row 1235 feet long was left unsprayed. The dates of spraying 

 were: August i, 8, 21, September 3 and 11. As "bugs " were at 

 no time sufficiently numerous to do damage no poison was used, 

 not even on the unsprayed row. The bordeaux was of the i-to-8 



