130 REPORT OF THE BOTANICAL DEPARTMENT OF THE 
38 hours for one man and horse. Allowing 15 cents per hour 
for the man’s time and Io cents for that of the horse the expense 
for labor would be $9.50, which makes the total expense of 
spraying 13 acres 4 times $27.50. 
Experiment No. 55.— It is plainly unfair to spraying to include 
this experiment because the check rows were sprayed three 
times before the experiment began. Consequently, the gain of 
18 bu. 20 lbs. per acre should be credited to the last four spray- 
ings only. The dates of spraying were, June 22, July 5, 19, 
August 4, 10, 17 and September 1. Mr. Hitchings informs us 
that there was no late blight or rot and very little contrast 
between the sprayed and unsprayed rows. The test rows were 
in a two-acre field of the variety Carman No. 3. The average © 
yield for this field was 135 bushels per acre. 
Experiment No. 56.—Mr. Prole, who conducted this experi- 
ment, states that there was an unusually small amount of blight 
even on the unsprayed rows. During the last two weeks of 
growth the sprayed rows made a slightly better appearance than 
the unsprayed. Part of the spraying was done with one nozzle 
per row spraying five rows at a time and part of it with two 
nozzles per row spraying four rows at a time. 
Experiment No. 57.— The sprayer used was the same one used 
in Experiment No. 47. Mr. Salisbury states that there was very 
little late blight except at one end of the field, but that the plants 
died prematurely from some other cause. He thinks the yield . 
would have been larger if the potatoes had been planted later. 
They were planted May 17-22. 
Experiment No. 60.— Mr. Robert reports that there was scarcely 
any difference in appearance between sprayed and unsprayed 
rows in his experiment. There was very little if any blight, but 
both sprayed and unsprayed rows were somewhat affected with 
tip burn. The expense for materials and labor was $56.20. 
If we add to this an allowance for wear of the sprayer the 
expense of the spraying just about equals the value of the in- 
creased yield. 
Experiment No. 61.—There was no blight in this experiment. In 
1905 Mr. Brennan reported a gain of 209 bushels per acre due 
to spraying. 
Experiment No. 62.— Mr. Lyday states that the conditions for a 
large yield of potatoes have not been so favorable for many 
years as they were in 1906. During July and August frequent 
