138 REPORT OF THE BOTANICAL DEPARTMENT OF THE 
per row in the last one. Paris green was applied with the bordeaux 
only in the first two sprayings. 
Three rows 626 feet long were left unsprayed. Tlicse rows 
were treated with paris green frequently so that bugs did no harm, 
but in one application the plants were slightly injured by the paris 
green. 
The expense of the spraying was as follows: 
742. lbs. "copper sulphate -(@ 7c) ..cc it, -0. 1. eee ieee cee ee $5.18 
75 oF WLS TVLE Ny Segeemeae osu oe cae eae tee aint nie aaah 6 ae eee ae da 1.00 
) ie APATIS SQ T CEN HO) (25Cc Mie Von ek ete erie Ge eee 1.75 
7s NYslavporriOf .1nan and Norse (a) 25C.u04 vase. ceeee ee 1.88 
Wats GN -SSPTayerics¥.ox eo. wala dee we hae Winks renames Te ee ee 2.00 
Totals: wie ca's gem a ee os ce oe ce ee eee $11.81 
The total cost of spraying was $2.95 per acre or 98 cents per 
acre for each application. 
The test rows were dug September 29 with the following results: 
Second sprayed row on the north, 226 lbs. marketable tubers. 
Second sprayed row on the south, 231 lbs. marketable tubers. 
Average of two sprayed rows, 228% lbs. marketable tubers. 
Middle unsprayed row, 140 lbs. marketable tubers. 
Yield, sprayed, 99 bu. 56 lbs. marketable tubers per acre 
Yield, unsprayed, 61 bu. 14 lbs. marketable tubers per acre. 
Gain, 38 bu. 42 lbs. marketable tubers per acre. 
In this experiment, also, there was practically no loss from rot. 
Spraying increased the yield of marketable tubers 63.2 per ct. 
The yield of culls was 5 bu. 31 lbs. per acre for the sprayed and 
fourteen bushels for the unsprayed, making a difference of 8 bu. 
2g lbs. per acre in favor of the unsprayed. 
At 50 cents per bushel the value of the increase in this experi- 
ment would be $19.35. After deducting $2.95, the cost of spray- 
ing we have left a net profit of $16.40 per acre. 
Combining the results obtained in the two fields there is an 
average gain of 44 bu. Io lbs. per acre and an average net profit of 
$18.59 per acre. 
The gain in both these experiments seems to have been due 
chiefly to protection against late blight. There was no trace of the 
disease in either experiment on August 1, but it appeared soon 
after and wrought serious injury to the unsprayed rows. Mr. 
