New York Agricultural Experiment Station. 149 



The average yield of the three varieties was 292 bushels and 37 

 pounds per acre for the sprayed rows and 285 bushels ^^ and 27 

 pounds for the unsprayed rows, making the increase in yield 7 bushels 

 per acre or 35 bushels on the five acres. 



In the first spraying bordeaux was applied at the rate of 81 gallons 

 per acre and in the second spraying 108 gallons per acre. Assuming 

 that the whole field had been sprayed three times and that the cost 

 of the third spraying was the same as for the second the expense 

 account would stand as follows : — 



156 lbs. copper siilpliate, at 7c $10 92 



198 lbs. lime 66 



102 hours' labor for man, at 15c 15 30 



51 hours' labor for boy, at 7^c 3 83 



51 hours' labor for horse, at loc 5 10 



163^ lbs. paris green, at 15c 2 48 



Wear on sprayer i 71 



Total $40 GO 



Since the total gain due to sprayitig was only 35 bushels of pota- 

 toes worth $17.50, there was a loss of $22.50 which is at the rate 

 of $4.50 per acre. It should be observed, however, that the expense 

 of spraying was unusually large ; namely, $2.67 per acre for each 

 application. In the other business experiments reported in this bul- 

 letin the cost per acre for each spraying ranged from 39 to 98 cents. 

 With a reasonably large expense for spraying the Dobson field would 

 have paid expenses. 



In the Dobson experiment the spraying was done in a business-like 

 manner, but the trouble lies with the method. It is too slow and 

 requires too much man labor. However, had there been a severe 

 attack of blight it is likely that the very thorough spraying would 

 have given results which would have compared very favorably with 

 those obtained in the other experiments. 



"Owing to portions of the field being damaged by heavy rains early in 

 the season this average was not t^iaintained throughout the field. The total 

 yield of the five acres was about 1,200 bushels. 



