New York Agricultural Experiment Station. 



131 



Comments on the table. — Again, as in 1902, the difference in yield 

 between the sprayed and unsprayed rows was much smaller at River- 

 head than at Geneva. There was a severe attack of late blight 

 (Phytophthora) which was only partially prevented by the spray- 

 ing, even on the rows sprayed every two weeks. Toward the close 

 of the growing period the plants were attacked by hordes of hungry 

 flea-beetles coming from the neighboring blighted fields. Since the 

 unsprayed rows were already dead, the sprayed rows, alone, suffered 

 from this attack and the death of the plants was undoubtedly hast- 

 ened. Had it not been for flea-beetles the difference in yield between 

 the sprayed and unsprayed rows would probably have been consider- 

 ably greater. 



In all four sections each of the sprayed rows yielded more than 

 the unsprayed row, and. with one exception, Section C, the row 

 sprayed five times outyielded the row sprayed three times. It 

 is not known how it came about that Row 7 (sprayed three 

 times) yielded six bushels per acre of marketable tubers more 

 than Row 8 (sprayed five times). 



Yield by series. — The yield by series is shown in the following 

 table: 



Table VI. — Yield by Series at Riverhead. 



Increase in yield due to spraying three times, SpYi bushels per acre. 

 Increase in yield due to spraying five times, 5<5 bushels per acre. 



Loss from rot. — Among the tubers from the sprayed rows there 

 was only occasionally one affected with rot. By actual count 

 there were only eight rotten tubers on the four rows of Series 



