REPORT OF THE BOTANIGAL 
DEPARTMENT. 
Pee LO-sPRAYING "EXPERIMENTS IN. 1906.” 
Peep uis WAR). J..KUSTACE, G, T. FRENCH anp F. A. SIRRINE. 
SUMMARY. 
The fifth year of the ten-year series of potato-spraying experi- 
ments begun in 1902 is now completed. During 1906 the work 
was carried out along the same lines as in 1904 and 1905. Eighty 
Separate experiments are reported in this bulletin. 
TEN-YEAR EXPERIMENTS. 
At Geneva, five sprayings increased the yield 63 bushels per 
acre, while three sprayings increased it 31.75 bushels. The gain 
was due chiefly to the prevention of late blight. There was no 
rot. At Riverhead, the gain due to five sprayings was 53.25 bushels 
per acre and to three sprayings 21.5 bushels. Here, the chief ene- 
mies were the flea beetle and late blight, but there was no rot. 
FARMERS’ BUSINESS EXPERIMENTS. 
In fifteen experiments, including 225.6 acres, the average gain 
due to spraying was 42.6 bushels per acre; the average total cost 
of spraying, $5.18 per acre; the average cost of each spraying, 
98.5 cents per acre; and the average net profit, $13.89 per acre. 
VOLUNTEER EXPERIMENTS. 
Sixty-two volunteer experimenters, spraying 598 acres, re- 
ported gains averaging 44.5 bushels per acre, the largest being 
132.6 bushels and the smallest no gain at all. 
*A reprint of Bulletin No. 290. 
