248 Report of the Department of Botany of the 



Average yield of unsprayed rows, 108.23 bu. per acre. 



Average yield of the rows sprayed by the Station, 126 bu. per acre. 



Average increase in yield per acre, 17.76 bu., or 16.4 per ct. 



Table II. — Results of Thorough Spraying of Single Rows in Nineteen 



Sprayed Potato Fields. 



Average yield of rows sprayed only by owner, 134.7 bu. per acre. 

 Average yield of rows sprayed also by the Station, 149.74 bu. per acre. 

 Average increase in yield per acre, 15.04 bu., or 11.2 per ct. 



comments on the results. 



The increase in yield due to spraying was small compared with that 

 usually obtained by very thorough spraying. However, it is as 

 large as could be reasonably expected when it is considered that the 

 conditions were extremely unfavorable. In dry seasons when there 

 is little or no blight the increase in yield from spraying is largely 

 dependent upon the fact that sprayed plants live considerably 



