28 
Journal of Agricultural Research 
Vol. XXXI, No. 1 
healthv milkweed plants in the Olin plat were marked during the 
early fall, and in November a portion of the roots of these plants 
was dug and placed in 10-inch pots in the greenhouse. In most cases 
the roots of mosaic and healthy plants were grown in separate pots, 
but in two instances mosaic and healthy roots were planted together. 
The roots in practically every instance sent up from one to two 
shoots during the early part of February and it was possible to 
determine the presence of mosaic on such shoots. From the results 
given in Table XII, which includes all such plants, it will be seen 
that the roots of mosaic plants produced shoots which were mosaic 
diseased in every case (pi. 2, C). The roots of the supposedly healthy 
plants, however, developed healthy shoots in all instances. In the 
two pots in which both healthy and mosaic roots were placed, both 
healthy and mosaic shoots were produced. 
Table XII .—Results obtained from growing roots of healthy and mosaic milk¬ 
weed plants in the greenhouse at Madison, Wis ., and inoculating healthy cucum¬ 
bers from the plants thus produced 
Roots 
(brought 
in on 
Nov. 10, 
1920) 
Character of 
roots 
Manner of in¬ 
fection 
Type of shoots 
produced 
Number 
of cucum¬ 
ber plants 
inoculated 
from 
shoots 
Method of inocu¬ 
lation 
Number 
of plants 
mosaic 
1-1 
Mosaic 
Inoculated. 
Mosaic __ 
4 
Aphids_ 
3 
7-1. 
_do . __ __ 
_do_- 
_do _ 
4 
..-'—do_ 
2 
8-1 
_ .do . _ 
Natural_ 
_do_ 
10 
_do _ 
8 
8-2 . 
_do_ 
_do_ 
_do__ --_ 
None_ 
9-1 
_do__ 
_do.. 
9-2 
_do_ 
_do_ 
_do.. 
3 
Aphids_ 
1 
12-1 _ 
_do_ 
_do.. 
_do_ 
2 
_do... 
0 
12-2 . 
_do_ 
_do_ 
_do_ 
3 
_do_ 
2 
13-1 
_do 
Inoculated__ 
_do_ 
9 
Aphids and arti- 
8 
fieial. 
13-2. 
_do_ 
_do_ 
_do_ 
7 
_do__ 
3 
14-2 
rio 
Natural 
... _do_- 
None. 
17-1 
_ .do— . 
Inoculated-- - _ 
...!_do__ 
4 
Artificial__ 
3 
17-2 
do 
do 
_ __do_ 
None__ 
19-1.. 
__do_ _ 
Natural_ 
.do... 
2 
Aphids_ 
i 
19-2 
do . 
_do_ 
_do_ 
2 
.....do__ 
2 
9-H2 * 
Healthy 
Healthy_ 
4 
_do.__ 
0 
10 -1° 
__ .do 
_do__ 
4 
_do... 
0 
10-2 a 
do 
_do__ 
6 
Artificial.. 
0 
11 -1° 
do 
__ .do_ 
None.. __ 
1/5—2 
15-3 
_do 
_do_ 
4 
Aphids_ 
0 
A-l 
do 
_do_. ___ 
None__ 
A-3 
A-4 
do 
do . _ _ 
A-5 
do 
do 
.do—.. -. 
A-fi 
do 
_do.. 
_do.- 
A-7 
do 
___ _do... 
8 
Aphids_ 
0 
A-8 . 
. ..do _ - 
_do.. 
8 
.do.. 
0 
A-9_ 
_do_ 
_ __.do__ 
8 
_do_ 
0 
A-10_ 
_do.. 
_do_ 
None... 
* Roots of plants used as controls for plants indicated as "Inoculated” in Table XI. 
These results, as shown in Table XII, were confirmed by a con¬ 
siderable number of inoculations from both the healthy and mosaic 
milkweeds to healthy cucumber plants. Inoculations in this case 
were made successfully both by means of aphids and by artificial 
inoculation with the crushed leaf tissues of the milkweed. It was 
also found that the roots of milkweeds inoculated with cucurbit 
mosaic in the field produced mosaic shoots in every case, while the 
roots of the controls of these experiments produced only healthy 
shoots. 
