244 REPORT CF THE DEPARTMENT OF BOTANY OF THE 
POTATO SPRAYING EXPERIMENTS IN 1907.* 
F.C, STEWART, (Gt. FRENCH AND 3A. ree eee 
SUMMARY. 
This bulletin gives the results of the sixth year’s work in the ten- 
year series of potato spraying experiments begun in 1902. During 
1907 the experiments were conducted along the same lines as in 
previous years. Forty separate experiments are reported. 
TEN-YEAR EXPERIMENTS. 
At Geneva five sprayings increased the yield 73.7 bu. per acre 
and three sprayings increased it 44 bu. notwithstanding the fact 
that the:amount of damage done by blights and insects was seem- 
ingly small. There was no rot. At Riverhead the gain due to six 
sprayings was 31.25 bu. per acre and to three sprayings 18 bu. 
Here, the chief enemies were the flea beetle and early blight. 
FARMERS’ BUSINESS EXPERIMENTS. 
In fourteen farmers’ business experiments, including 152.75 acres, 
the average gain due to spraying was 36.8 bu. per acre; the aver- 
age total expense of spraying, $5.90 per acre; and the average net 
profit, $17.07 per acre. 
VOLUNTEER EXPERIMENTS. 
Twenty-four volunteer experimenters reported gains averaging 
20.5 DU per acre, 
The chief troubles of potatoes in New York in 1907 were flea 
beetles and dry weather. The experiences of 1907 do not warrant 
any material alteration in the recommendations for spraying made 
in Bulletin 290. 
*A reprint of Bulletin No. 307. 
