834 Popular Editions of Station Bulletins of the 



A little earlj blight affected the iinsprayed rows, but there was 

 no late blight in the field at any time. In spite of these, unprom- 

 ising conditions for spray benefit a difference between sprayed and 

 unsprayed rows was evident from the middle of September until 

 frost came ; and the yields, as shown below, again proved spraying 

 beneficial in spite of the absence of any very evident reasons for 

 that benefit. 



♦ Marketable tubers only. 



Increase in yield due to spraying three times, 40 hu. per acre. 

 Increase in yield due to spraying seven times, 93 bu. per acre. 



At Riverhead flea beetles were abundant. There was a little 

 early blight, but no late blight or rot. Severe drought caused early 

 death of the plants on all three series, thus reducing the yields to 

 a very low point and preventing any chance of benefit from the 

 spraying. 



Table III. — Yield by Series at Riverhead in 1911. 



Increase in yield due to spraying three times, li hu. per acre. 

 Increase in yield due to spraying five times, ^ hu. per acre. 



