128 REPORT OF THE BOTANICAL DEPARTMENT OF THE 
puted in the same manner. The yield by series is shown in the 
following table: 
TaBLeE VIII.—YIELD By SERIES AT GENEVA. 





SERIES. Rows.® Dates of spraying. Yie d per acre 
i a Bikol Ae ek Os 7d eae Bu. Lbs. 
je 5 Ae 4.07, LObANGuloh gad July 3; ACpust’7 and Zon. eee 228 45 
Serre oF 518.4. Liands 1 4eee ee June 29, July 13, 27, August 12 and 24.| 241 15 
Scan ee eee 6.9. Los beer =a Not-sprayéd ache aoe te ee eee 121 De 



8 The rows of Section A (Nos. 1, 2 and 3) have been omitted because of error, 
Increase in yield due to spraying ‘three times, 107 bu. per acre. 
Increase in yield due to spraying five times, 1194 bu. per acre. 
This year the difference in yield between Series I, sprayed three 
times, and Series II, sprayed five times, was less than ever before, 
being only 12%4 bushels per acre. Considering that there was no 
apparent difference in the foliage no marked difference in yield was 
to be expected. 
Loss from rot.—The loss from rot was greater than in any ot 
the preceding experiments. Owing to the fact that some of the 
affected tubers were in an advanced stage of decay it was impossible 
to determine accurately the loss from rot, but on each row the 
approximate weight of rotten tubers was ascertained. It was found 
that on Series I, sprayed three times, the loss from rot was at the 
rate of 6 bu. 4o Ibs. per acre; on Series II, sprayed five 
times, 6 bu. 15 Ibs. per acre; while on Series III, not sprayed, 
it was 47 bu. 30 lbs. per acre. In other words spraying 
reduced the loss from rot by 41 bushels per acre. Such 
was the situation at digging time. It sometimes happens that 
potatoes apparently sound at digging time subsequently decay in 
storage. This happened in the ten-year experiment at Geneva in 
1904. (See foot note on page 112 of Bulletin 264). In order to 
determine the extent of such loss in the 1905 experiment the tubers 
from each of three rows (Rows 8, 9 and 10) were stored in crates 
in a good cellar from October 21 until December 9 and then ex- 
amined. In the four and one-half bushels of tubers from Row 8 
there were only two affected tubers; in two and one-half bushels 
from Row 9g there were also two affected tubers while in the four 
and one-half bushels from Row to not a single tuber showed signs 
of rot. The potatoes were not sorted more carefully at digging 
time in 1905 than in 1904. Our opinion is that in 1904 the potatoes 
were dug too soon after the tops died. 
