July 14,1923 
Degeneration Diseases 0 } Irish Potatoes 
105 
fact that leaf roll did not reach the tubers in hills adjacent to leaf-roll 
hills in this field until after August 13, and then only in small amount, 
may be due to the greater difficulty of effective leaf-roll inoculation 
compared with mosaic, or to slower diffusion of the virus in the plant, 
or to both. 
Table XXVII .—Mosaic and leaf roll uncontrolled inoculations in the field in IQ 20 1 
Location in 1920. 2 
Series. 3 
Hills. 
Progeny, 1921. 
Tuber 
units. 
Mosaic. 
Leaf 
roll. 
Per cent. 
Per cent. 
I-A 
10 
39 
3 
O 
In field A, next to mosaic hills. 
l-B 
‘ I-C 
10 
10 
42 
42 
5 
69 
O 
O 
i-D 
10 
44 
48 
O 
2-A 
10 
41 
2 
O 
In field A, next to leaf-roll hills. 
2-B 
' 2-C 
10 
10 
43 
33 
9 
16 
O 
O 
. 2-D 
10 
38 
18 
18 
3 - A 
10 
4 i 
0 
O 
In field A, in healthy plot. 
3 “B 
3 ~C 
10 
10 
48 
42 
6 
0 
O 
O 
3 -D 
10 
39 
15 
O 
4 -A 
10 
42 
0 
O 
In field B (rogued), next to sites of rogued hills. 
4 -B 
4 -C 
10 
10 
40 
45 
13 
7 
O 
0 
4 -D 
10 
3 1 
19 
O 
5 -A 
10 
42 
0 
O 
In field B, not next to sites of rogued hills. 
5 -B 
5 -C 
10 
10 
44 
44 
2 
5 
0 
O 
5 -D 
10 
37 
0 
O 
6-A 
10 
48 
8 
O 
In field C, next to mosaic hills. 
6-B 
10 
47 
17 
O 
6-C 
10 
47 
15 
O 
7 -A 
10 
44 
5 
O 
In field C, not next to diseased hills. 
7 -B 
10 
47 
*3 
O 
7 -C 
10 
45 
16 
O 
8-A 
5 
25 
16 
O 
Irish Cobblers in field C, next to leaf-roll hills.. 
8-B 
8-C 
5 
5 
24 
19 
42 
5 
O 
O 
8-D 
5 
25 
20 
O 
9 ~A 
5 
25 
4 
O 
Irish Cobblers in field C, not next to leaf-roll 
9-B 
5 
22 
18 
O 
hills. 
9 -C 
5 
23 
0 
O 
9 -D 
5 
25 
4 
O 
10-A 
10 
49 
2 
O 
In field D (rogued), on soil in which mosaic 
10-B 
10 
48 
0 
O 
plants grew in 1919. 4 . 
10—C 
10 
47 
6 
O 
* 
10-D 
10 
43 
5 
O 
: 11-A 
10 
4 i 
0 
O 
In field D, on soil in which healthy plants 
n-B 
10 
47 
2 
O 
grew in 1919. 
11-C 
10 
47 
2 
O 
11-D 
10 
44 
7 
O 
1 Green Mountains except for Series 8 and 9. 
2 Except for field D, with 2 years elapsing with no potatoes grown on the soil. 
3 Each series consists of subseries according to the dates of harvesting, which are, respectively, July 29-30 
(A), Aug. 12-13 (B), Aug. 23-24 (C), and Sept. 15 (D). ...... . . t .... . . . 
4 No volunteers present because all tubers in the soil were killed by a severe winter with snowfall hght in 
the early part. 
