POTATO SPRAYING EXPERIMENTS, 1902-191L* 



F. C. STEWART, G. T. FRENCH and F. A. SIRRINE 



SUMMARY. 



This bulletin gives a detailed account of the potato spraying 

 experiments conducted by the Station in 19 ii and a summary 

 of results obtained in similar experiments made during the nine 

 years preceding. 



In the so-called ten-year experiments the ten-year average 

 increase in yield is as follows: 



At Geneva, three sprayings, 69 bu. per acre. 



At Geneva, five to seven sprayings, 97.5 bu. per acre. 



At Riverhead, three sprayings, 25 bu. per acre. 



At Riverhead, five to seven sprayings, 45.7 bu. per acre. 



In the farmers' business experiments (6 to 15 each year) the 

 nine-year averages are as follows: 



Increase in yield, 36.1 bu. per acre. 



Total expense of spraying, $4.74 per acre. 



Net profit from spraying, $14.43 per acre. 



In 205 volunteer experiments, covering seven years, the aver- 

 age increase in yield was 54.3 bu. per acre. 



These experiments demonstrate, beyond doubt, that the spray- 

 ing of potatoes is highly profitable in New York. 



Spraying with bordeaux mixture should be commenced when 

 the plants are six to eight inches high and repeated at intervals 

 of 10 to 14 days throughout the season, making five to seven 

 applications in all. Some poison should be added to the 

 bordeaux whenever bugs or flea beetles pre plentiful. The 

 spraying should be very thorough — the more thorough the 

 better. 



INTRODUCTION. 



Does it pay to spray potatoes in New York? Potato growers 

 have long asked this question. It is well known that in seasons 



*A reprint of Bulletin No. 349, June, 1912; for "Popular Edition," see 

 p. 831. 



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