New York Agricultural Experiment Station. 135 



gun to prevent injury from " bugs." The yield of marketable tubers 

 on the uhsprayed row was 514 pounds which is at the rate of 274 

 bushels per acre. The adjacent sprayed row yielded 615 pounds 

 which is at the rate of 328 bushels per acre. Thus the increase in 

 yield due to spraying was 54 bushels per acre or a total of 702 bushels 

 on the 13 acres. 



The items of expense for spraying 13 acres four times are as 

 follows : 



294 lbs. copper sulphate, at 6c $17 64 



80 lbs. pan's green, at i8c 14 40 



I barrel lime i 35 



Repairs on spraying outfit i 50 



45 hours labor for man, at 20c 9 00 



45 hours labor for horse, at loc • 4 50 



Interest on investment ($42) at 6% 2 52 



Total $50 91 



The average cost per acre of each spraying was 98 cents. 



This experiment was conducted throughout by Mr. Jagger. When 

 the fields were visited by one of the writers on August 13 the un- 

 sprayed row had already lost about three-fourths of its foliage from 

 late blight, PliyfophtJiora infcstans. The sprayed portion of the field 

 was still very green and only slightly injured, but Phytophthora was 

 plentifuh among the plants. At this time nearly all unsprayed potato 

 fields in the vicinity were dead and brown. Some farmers who were 

 digging and marketing their crops reported only traces of rot. How- 

 ever, a few days later there was considerable rot. In some fields 

 as much as two-thirds of the crop rotted. 



Mr. Jagger reports that_ there was some rot all over his sprayed 

 fields, but it was much worse on the unsprayed row. It is likely 

 that more thorough spraying would have resulted in a considerably 

 larger yield on the sprayed fields. 



