POTATO SPRAYING EXPERIMENTS AT RUSH 



IN 1913* 



F. C. STEWART. 

 SUMMARY. 



During the summer of 19 13 an extensive series of potato-spraying 

 experiments was conducted in the vicinity of Rush, N. Y. In each 

 of 66 fields a portion of one row (one-fiftieth acre) was very 

 thoroughly sprayed by hand every two weeks. At digging time the 

 yield of this row was compared with that of an adjacent row which 

 had not received the special spraying. In 47 of the fields no spraying 

 was done by the owner. In these fields the test was a comparison 

 between very thorough spraying and no spraying. In the other 

 19 fields more or less spraying was done by the owner. In these, 

 the test was a comparison between very thorough spraying and the 

 kind of spraying done by the owner. 



In the 47 unsprayed fields the spraying done by the Station 

 increased the average yield by 17.76 bushels per acre, or 16.4 per ct. ; 

 and in the 19 sprayed fields, by 15.04 bushels per acre, or 11.2 

 per ct. 



It is believed that the increase obtained was due to the partial 

 control of tip-burn which was quite plentiful in some fields, the 

 better control of Colorado potato beetles (not well controlled by 

 the owner in a few cases), and stimulation of the plants. Late 

 blight was entirely absent and early blight and flea beetles scarce. 

 Probably, the gain from spraying would have been considerably 

 larger had not the plants been killed prematurely by an early frost. 



PRESENT PROBLEMS IN POTATO SPRAYING. 



It pays to spray potatoes in New York. That has been con- 

 clusively proven by the numerous experiments made by this Station. 

 Further experimentation along that line is unnecessary. Never- 

 theless, there is still something to be learned from potato spraying 

 experiments. There is reason to believe that the present methods 

 of spraying may be considerably improved. For one thing, it is 

 probable that potato-growers would find it profitable to spray more 

 thoroughly than they are now doing. Probably, lack of thorough- 

 ness is the chief fault of the present methods. Although some are 

 spraying quite thoroughly, many New York potato-growers are 



* Reprint of Bulletin No. 379, March ; for Popular Edition see p. 918. 



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