132 



Report of the Botanist of the 



II. On the unspraycd rows the loss from rot was about two 

 per ct. 



AS SHOWN BY CHEMICAL ANALYSIS. 



In the experiment at Geneva in 1902, fifty consecutive hills 

 from a row sprayed seven times and the same number of hills 

 from an adjacent unsprayed row were analyzed in order to deter- 

 mine whether spraying had affected the chemical composition of 

 the tubers. It was found that the sprayed potatoes contained a 

 larger percentage of dry matter which consisted mostly of starch. 

 (See Bulletin 221, page 254.) 



A similar analysis was made in 1903. Fifty hills of potatoes 

 sprayed five times and fifty liills of unsprayed potatoes were selected 

 from the experiment at Geneva and analyzed. Unfortunately, the 

 selection of these hills was neglected until the digging had progressed 

 so far that it was impossible to secure 50 consecutive hills in any of 

 the rows. Instead, it was necessary to take 25 consecutive hills from 

 each of two sprayed rows (Rows 8 and 14) and 25 consecutive hills 

 from each of two unsprayed rows (Rows 3 and 6). Thus the 

 sprayed and unsprayed hills were not taken from adjacent rows. 

 They were taken, however, from the same portion of the field ; 

 namely, at the south end, where the blight was least destructive. 



The following analysis was made by Mr. F. D. Fuller : 



Table VII. — Charactkr and Composition of Sprayed and Unsprayed 



Potatoes. 



yield and size of tubers. 



