242 Report of the Botanical Department of the 



the glen head experiment. 



Conducted bj G. T. Powell, Glen Head, Long Island. Fifteen 

 acres of potatoes were sprayed five times (June 14, 29, July 14, 

 20, and August 7) with bordeaux applied by means of a one- 

 horse, four-row " 'Spramotor " sprayer carrying two nozzles per 

 row. Four rows were left unsprayed for a check. Four rows on 

 each side of the <iheck were double-sprayed. Arsenite of soda was 

 used wath the bordeaux in the first two sprayings at the rate of 

 3 qts. of the stock solution to 50 gals, of bordeaux. The check 

 was kept free from bugs by one application of lead arsenate. 

 Flea beetles w^ere numerous and there was much tip bum but no 

 blight. A marked contrast between the sprayed and unsprayed 

 rows indicated that spraying had checked both tip bum and flea 

 beetles, but when the yields were taken very little difference was 

 found between the single-sprayed rows and the check. This leads 

 us to suspeet that, in some way, the experiment was unfair. 



The items of expense were as follows: 



450 lbs. copper sulphate @ 5 cts ?22 50 



Lime 6 00 



100 lbs. sal soda @ IVa cts 1 50 



40 lbs. white arsenic @ 3 cts 1 20 



75 hrs. labor for man and horse @ 25 cts , 18 75 



Wear of sprayer 5 00 



Total $54 95 



Expense per acre for five sprayings, $3.66. 



Expense of spraying one acre once, 73 cents. 



The test rows (variety Green Mountain) yielded as follows: 



Average yield of two double-sprayed rows, 166.5 bu. per acre. 



Average yield of two single-sprayed rows, 147.7 bu. per acre. 



Yield of one check row, 145.5 bu. per acre. 



Gain due to double-spraying, 21 bu. per acre. 



Gain due to single-spraying 2.2 bu. per acre. 



Potatoes being worth $3 per barrel of 174 lbs. (= $1.03 per 

 bu.), single-spraying resulted in a loss of $1.40 per acre, while 

 double-spraying gave a net profit of $14.31 per acre. 



