July 1, 1925 
Overwintering and Dissemination of Cucurbit Mosaic 
51 
pepper. Such a possibility was of interest, owing to the fact that a 
large number of inoculations had been made from mosaic cucumber 
plants to tobacco, and vice versa, without obtaining any evidence that 
either of these mosaic diseases was transmissible to the other host. 
The symptoms on the pepper were so similar, however, when the 
plants were inoculated either with tobacco or cucumber mosaic, that 
it seemed possible that the diseases on tobacco and cucumber were 
at least intertransmissible if not identical. 
Experiments were undertaken, therefore, in which pepper plants 
were inoculated with cucurbit mosaic, both by means of aphids and 
by artificial methods of inoculation. The plants used in these 
experiments were grown in a greenhouse which contained no other 
mosaic plants and were kept covered with cheesecloth cages during the 
experiment. Control plants were kept under separate cages in each 
series of inoculations. After mosaic symptoms had developed on the 
peppers thus inoculated with cucurbit mosaic, inoculations were made 
from them to healthy cucumber and tobacco plants. The same pep¬ 
per plant was used as a source of inoculum for both hosts and control 
plants were placed under separate cages. In the case of the cucumber, 
the inoculations were made by means of aphids and also by artificial 
methods, using the juices of the mosaic pepper. The tobacco 
plants were inoculated only by the latter method. In all of these 
experiments, as shown in Table XXI, a high percentage of infection 
occurred on both cucumber and tobacco plants when inoculated 
from peppers affected with cucurbit mosaic.* The controls remained 
healthy in all cases. The symptoms produced on the tobacco plants 
appeared to be the same as those produced on other tobacco plants 
inoculated with tobacco mosaic for comparison, and the incubation 
period was the same in both cases. This also held true in the case 
of the incubation period of cucumbers inoculated from mosaic cu¬ 
cumber plants when compared with those inoculated from the pepper. 
Table XXI .—Results of cross inoculations of cucumber and tobacco plants from 
pepper plants infected with cucumber mosaic 
Date of 
inocula¬ 
tion, 1922 
Pepper plant used 
as inoculum 
Plant 
inoculated 
Method of inoculation 
Number 
of plants 
inocu¬ 
lated 
Number 
of plants 
mosaic 
Date 
ob¬ 
served, 
1922 
Aug. 19 
2-e (mosaic)_ 
Tobacco_ 
Artificial___ 
10 
6 
Aug. 27 
Do_ 
1 (healthy)_ 
...do.. 
Control. ... 
10 
0 
Do. 
Do 
2-e (mosaic). _ 
Cucumber. _ 
Artificial_ 
6 
4 
Aug. 26 
Do ... 
.do... 
_do_ 
Aphids from mosaic pepper 
6 
6 
Do. 
plant. 
Do.— 
1 (healthy)_ 
_do_ 
Aphids from healthy pepper 
6 
0 
Do. 
plant (control). 
Oct. 4 
3-H (mosaic). _ . 
Tobacco 
Artificial. _ _ 
10 
7 
Oct. 12 
Do. 
4 (healthy) 
do_ 
Control _ 
10 
0 
Do. 
Do 
3-H (mosaic) 
Cucumber 
Artificial__ 
9 
4 
Oct. 10 
Do- 
.do_ 
_do_ 
Aphids from mosaic pepper 
9 
9 
Do. 
plant. 
Do— 
4 (healthy) 
_do_ 
Aphids from healthy pepper 
9 
0 
Do. 
Nov. 7 
6-R (mosaic) 
Tobacco _ . 
plant (control). 
Artificial__ 
6 
5 
Nov. 15 
Do_ 
2 (healthy)_ 
_do_ 
Control_ _ 
6 
0 
Do. 
Do 
6-R (mosaic) 
Cucumber. _ 
Artificial_ 
8 
4 
Do. 
Do.... 
2 (healthy)... 
_do_ 
Control.. !- 
6 
0 
Do. 
Inasmuch as these experiments indicated that cucumber mosaic 
could be transmitted to tobacco through the use of the pepper as an 
intermediate host, another series of inoculations was made in which 
