82 
Journal of Agricultural Research 
Vol. XXV, No. 2 
The plants in Series i to io reached Stage I during the last half of Decem¬ 
ber and Stage II about the middle of January, and were dug up mostly 
in February. The progeny were planted in the field in May and were 
observed in August, which was cool, when they showed more distinct 
mottling than the all-mosaic stocks that were observed in June and July, 
which were warm and dry, at corresponding stages that are usually the 
best for mosaic diagnosis. 
Table XIX.— Inoculations of Green Mountains in the Orono , Me ., greenhouse in the 
winter of 1920-21 
Inoculation. 
Inoculated plants. 
1920 - 21 . 
Progeny, 1921 . 
Series. 
I 
2 
3 
4 
5 
6 
7 
8 
9 
10 
SI 
Method. 
Juice rubbed into mutilated leaves 
over entire plant (PI. 13, A). 
Juice rubbed into mutilated leaves 
of lower third of stem. 
Juice rubbed into mutilated leaves 
of upper third of stem. 
Stem split in lower part and a por¬ 
tion immersed for several days in 
a vial full of juice (PI. 14, A). 
Stem split in upper part and a por¬ 
tion immersea for several days in 
a vial full of juice. 
Capillary tubes full of juice in¬ 
serted in lower part of stem. 
Capillary tubes full of juice inserted 
in upper part of stem (PI. 13, B). 
As for Series 1 
As for Series 2 
As for Series 3. 
Sources of inoculum 
Time . 1 * 
I 
II 
III 
IV 
I 
II 
III 
IV 
I 
II 
III 
IV 
I 
II 
III 
IV 
I 
II 
III 
IV 
I 
II 
III 
IV 
I 
II 
III 
IV 
II 
II 
II 
II 
II 
II 
II 
II 
II 
II 
II 
II 
Hills. 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
3 
6 
Date 
dug.® 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
VIII 
V 
VI 
VII 
VIII 
V 
VI 
VII 
VIII 
V 
VI 
VII 
VIII 
Hills . 3 4 
13 
8 
12 
13 
13 
10 
11 
8 
II 
11 
9 
10 
9 
10 
12 
12 
12 
11 
13 
12 
11 
13 
11 
IO 
9 
10 
10 
13 
9 
11 
10 
11 
5 
10 
11 
6 
9 
11 
9 
10 
19 
Mosaic. 
Per cent. 
O 
38 
IOO. 
7 
o 
40 
27 
o 
o 
82 
67 
o 
o 
o 
o 
o 
o 
o 
o 
o 
27 
31 
o 
o 
o 
o 
20 
o 
100 
- as— 
o 
o 
o 
o 
33 
73 
67 
o 
100 
1 Dates of inoculation are designated as I, II, III, and IV, indicating, respectively, the time the plant 
reached a height of from 10 to 15 cm., the time the first flower-bud cluster was exposed preliminary to the 
abortive anthesis, the fifteenth day after II, and the thirtieth day after II. 
4 The date of digging was either 10 (V), 20 (VI), 30 (VII), or 40 (VIII) days after II. 
* Each grown from 1 tuber. 
