126 REPORT OF THE BOTANICAL DEPARTMENT OF THE 
e ® 
tion made August 31 we conclude that the smaller yield of the 
unsprayed rows was partly due to a mild attack of late blight 
and partly to a browning of the leaves resembling tip burn 
which seemed to have been partially prevented by spraying. 
Experiment No. 33.—It is reported that there was not much 
blight in this field except at one end and here the unsprayed row 
died earlier than the sprayed ones. The unsprayed row was not 
injured by “bugs” and there was no rot among the tubers. 
The total yield of marketable potatoes on eight acres was 1,826 
bushels or 228 -+ bushels per acre. 
Experiment No. 34.— Thirty barrels of bordeaux mixture were 
used in spraying the six acres seven times. In the spring of 
1906 Mr. Norris erected a “ bordeaux platform” which proved 
a great convenience and saved considerable time. With this 
arrangement he could fill his sprayer and be off for the field 
again in ten minutes, while by the old method of pumping water 
and filling the sprayer by hand at least thirty minutes were re- 
quired. We are under obligations to Mr. Norris for the descrip- 
tion and illustration of his platform shown in Plate II. 
The items of expense for spraying 6 acres 7 times were as 
follows: 
205 lbs. copper ‘sulphate @ ‘$144@...0 22059 a $10.76 
5 ‘De Thinte (D256). faa POOL Re, Oa Oe ee 1.25 
33 hts:olabor: for, man. @ ASF in... vs deen Wa» oe nile «nes 4.95 
83. hrs. Jabor for horse @ 106.1). os vce pide ekg ae bx sii ee 3.30 
ST OUAL Ne ae le a hohe e over ace he Bie Eonldinlo yiete'h va at aoe ete dey a tee ak on tae enn $20.26 
Mr. Norris states that the unsprayed rows showed blight 
about ten days earlier than the sprayed, but that there was not 
much blight at any time so that the contrast between sprayed 
and unsprayed rows was not great. There was no rot. 
Experiment No. 35.—In this experiment there were four un- 
sprayed rows. The gain due to spraying was determined by 
comparing the yield of four of the unsprayed rows with that 
of four sprayed rows nearby. The yields were as follows: 
Four sprayed rows, 3,360 lbs. = 248 bu. 47 Ibs. per acre. 
Four unsprayed rows, 2,790 lbs. = 206 bu. 35 Ibs. per acre. 
Gain, 42 bu. 12 lbs. marketable tubers per acre. 
We saw this experiment twice — July 18 and August 6. At 
the time of our first visit late blight was just beginning to appear 
here and there all along the unsprayed rows. ‘There was also a 
