136 Report OF THE BoTANICAL DEPARTMENT OF THE 
the unsprayed by at least two weeks; and all experience as well 
as carefully conducted experiments at the Vermont Station” 
go to show that the growth of tubers is rapid during the later 
growth of potato plants. 
Thinking that there might have been some mistake some- 
where, two other rows, one sprayed and the other unsprayed, 
were dug and weighed. The rows selected for this second trial 
were the second unsprayed row from the south and the fourth 
sprayed row on the south, so there were four rows between. The 
results were as follows: : 
Sprayed row 815 pounds, or 300 bushels 11 pounds market- 
able tubers per acre. 
Unsprayed row, 751 pounds, or 276 bushels 37 pounds mar- 
ketable tubers per. acre. | 
Gain, 64 pounds, or 28 bushels 34 pounds marketable tubers 
per acre. 
Although the second trial showed somewhat better results 
than the first one the gain was still smaller than it ought to 
have been. Probably there was no mistake in taking the yields, 
but we are satisfied that in some way the unsprayed rows had 
an advantage. Where the trouble lies it has been impossible to 
determine. Sprayed and unsprayed rows were of the same 
variety, planted and cultivated in the same way, on the same 
kind of soil and with the same amount of fertilizer so far as 
known. Mr. Satterly is unable to explain it... He was as much 
surprised aS we were. 
We are convinced, however, that Mr. Satterly’s actual gain 
from spraying was more than 14 bushels per acre. . The large 
average yield obtained supports this opinion. The total yield of - 
marketable potatoes from 1514 acres was 4,838 bushels, which 
is at the rate of 312 bushels per acre. We do not believe that 
any unsprayed field of several acres on eastern Long Island gave 
an average yield as large as 300 bushels per acre in 1904. 
The items of expense of spraying ten times in the Mattituck 
experiment are as follows: 
479 pounds copper Sulphate ie CONUS: . wees $28 74 
SLES potas lime -'At) LeCen Cri cease ket. voc he oly sean reais | 3 16 

Vermont Exp. Sta. Bul. 40:26; Ann. Rep. 12: 155-156; Bul. 72:4—5. 
