82 REPORT OF THE BOTANICAL DEPARTMENT OF THE 
years. It is nearly one-fourth inch long, shiny black and jumps 
like the common flea beetle.® Its injury to potato foliage is simi- 
lar to that of the common flea beetle except that the gnawed 
areas are considerably larger. At this time there were very 
few of the common flea beetles, no early blight and no late 
blight; but later in the season some late blight appeared on the 
check rows. 
In Field No. 2, on August I, the unsprayed rows were distin- 
guishable from the sprayed rows only by a slight browning of 
the foliage due to injury from arsenite of soda. There were no 
common flea beetles and only a few of the larger kind. Early 
blight and late blight both were entirely absent; however, during 
the last month of their growth the plants on the unsprayed rows 
became slightly affected with late blight. 
In both fields the test rows were dug with a potato digger on 
October 25 with the following results: 
Field No. 1.—In this field the test rows were 849 feet long by 
34 inches apart. The yields were as follows: 
Second sprayed row on the east, 595% lbs. marketable tubers. 
Second sprayed row on the west, 69044 lbs. marketable tubers. 
Average of two sprayed rows, 643 lbs. marketable tubers. 
One of middle two unsprayed rows, 357% lbs. marketable tubers. 
Yield, sprayed, 194 bu. 5 lbs. marketable tubers per acre. 
Yield, unsprayed, 107 bu. 54 lbs. marketable tubers per acre. 
Gain. 86 bu. 11 lbs, marketable tubers per acre. 
Ficld No. 2.— In this field the test rows were 626 feet long and 
34 inches apart. ‘The yields were as follows: 
Second sprayed row on the north, 473% lbs. marketable tubers. 
One of the middle unsprayed rows, 440% lbs. marketable tubers. 
Yield, sprayed, 193 bu. 44 lbs. marketable tubers per acre. 
Yield, unsprayed, 180 bu. 14 lbs. marketable tubers per acre. 
Gain, 13 bu. 30 lbs. marketable tubers per acre. 
There was no loss from rot in either field. Combining the 
results obtained in the two fields we have an average gain of 
49 bu. 50 lbs. marketable tubers per acre. At the time of digging 
the test rows the market price of potatoes in Chafee was 40 cents 
per bushel. Thus the value of the increased yield was $19.93 
per acre. Subtracting $4.70, the expense of spraying, there 
remains a net profit of $15.23 per acre. Probably the actual profit 
was not quite as great as this. The lower yield of the unsprayed- 
6 Epitrix cucumeris Harr. 
