REPORT OF THE BOTANICAL 
DEPARTMENT. 
POVATO-SPRAYING EXPERIMENTS IN I9g05* 
F, C. Stewart, H. J. EUSTACE AND F. A. SIRRINE. 
SUMMARY. 
The fourth year of the ten-year series of potato-spraying experi- 
ments begun in 1902 is now completed. During 1905 the work was 
carried out along the same lines as in 1904. Seventy separate ex- 
periments are reported in this bulletin. 
TEN-YEAR EXPERIMENTS. 
At Geneva, five sprayings increased the yield 119% bushels per 
acre, while three sprayings increased it 107 bushels. The gain was 
due partly to prevention of late blight and partly to prevention of 
rot. At Riverhead, the gain due to five sprayings was 8&2 bushels 
per acre and to three sprayings, 311 bushels. Here, the flea beetle 
was the chief enemy. 
FARMERS’ BUSINESS EXPERIMENTS. 
In thirteen experiments, including 16524 acres, the average gain . 
due to spraying was 461% bushels per acre; the average total cost of 
spraying, $4.25 per acre; the average cost of each spraying, 98 cents 
per acre; and the average net profit, $20.04 per acre. 
VOLUNTEER EXPERIMENTS. 
In fifty experiments, including 407 acres, the average gain due 
to spraying was 591% bushels per acre. In 29 of these experiments 
the average total cost of spraying was $4.57 per acre; the average 
*A reprint of Bulietin No. 279.° 
11g 
