124 REPORT OF THE BOTANICAL DEPARTMENT OF THE 
The items of expense for spraying three acres four times were 
as follows: 
S4;lbs. ‘copper sulphate @)7¢. o.oo. ens buted aduie es iu) oe $5.88 
Sa tibs. inte sad sae ee ee ee eee .56 
Arsenite of) soda for! bugs 7 ay yee a a ae .60 
Labor: Van's. Gees Oh eileling by cc I ee ET Oe ei 4.00 
OTAL ene ego 't-a aki vip wit chy osama aus) Sistecar s Ac See) aie Nate ate at tr $11.04 
Experiment No. 24.— It is likely that a part of the gain in this 
experiment can not be properly credited to spraying. The un- 
sprayed rows were somewhat more injured by “bugs” which 
may have been due to the less thorough use of poison on the 
unsprayed rows. Mr. Driggs states that the sprayed rows re- 
ceived poison with the bordeaux on July 11, but as all of the 
“bugs” were not killed a second application of bordeaux and 
poison was made July 23. The unsprayed rows were treated 
with poison but once (about July 15) which seemed sufficient 
since the “bugs” were all killed. However, about a month 
later the unsprayed rows were again quite severely attacked 
while the sprayed rows were free from “ bugs.” 
Experiment No. 25.— When we saw this experiment August 18 
the three unsprayed rows were not distinguishable from the 
adjacent sprayed rows. Later there was some contrast, but 
Mr. Barry states that there was very little blight and no rot. 
Experiment No. 26.— Mr. Powell states that although there ap- 
peared to be very little blight and no injury from “bugs” the 
unsprayed rows died about two weeks earlier than the sprayed. 
There was no rot. 
Experiment No. 28.— The unsprayed rows were killed by blight 
about three weeks earlier than the sprayed rows. This experi- 
ment was made in a field of potatoes planted about the middle 
of June. The first spraying was made August 13. 
Experiment No. 29.—In this experiment the gain of nearly 
48 bushels per acre should be credited to the last three sprayings 
since in the first two sprayings the entire field was sprayed. 
Mr. Belden had already made the first two sprayings before 
receiving our letter requesting him to leave some unsprayed 
rows. Nevertheless, the sprayed rows outlived the check rows 
between two and three weeks. The expense for spraying mate- 
rials was $9. 
ae Ce a 
