6 
BULLETIN" 879, U. S. DEPARTMENT OF AGRICULTURE. 
The methods used in this inoculation work were very similar to 
those used in the other cucumber-mosaic studies. Where field inoc- 
ulations were made, the plants were protected with insect-proof 
cages wherever possible, and in the greenhouse all plants used in 
such inoculations were kept isolated from other mosaic experiments. 
The inoculum was prepared in much the same way as in other 
cucumber-mosaic inoculations, either the expressed juice or crushed 
tissues of mosaic plants being used. Where the juice of a mosaic 
plant was employed, the parts of the plant used as inoculum were 
passed through a sterilized food chopper and the juice expressed and 
filtered through filter paper. Inoculations were made at from three 
to five points in each of the younger leaves, a drop of the expressed 
juice being pricked into the leaf with a sterile needle. The stem 
usually was inoculated at one or more points, a slight incision being 
made with a sterile scalpel carrying a drop of the inoculum. 
Table I. — Record of inoculations from mosaic-* 
other families 
cucumber plants to plants of 
Plant inoculated. 
Preparation of inoculum. 
Number 
of plants 
inocu- 
lated. 
Results. 
Date inocu- 
lated. 
Number 
ofmosaic 
plants. 
Date last 
observed. 
Aug. 4,1916 
Mar. 11,1917 
Apr. 27.1917 
May 8 1917 
3 
4 
4 
8 
20 
18 
21 
3 
6 
4 
6 
15 
12 
15 
9 
6 
15 
10 
12 
8 
5 
6 
12 
10 
























Aug. 17,1916 
do 
do 
do 
do 
Mar. 26,1917 
Mav 28,1917 
'Do. 
.do 
....do 
Mav 20,1917 
Oct. 1 1917 
do 
.. .do.... 
Crushed leaf tissues 
do 
June 14,1917 
Oct. 30,1917 
Dec. 1, 1917 
Nov. 5, 1917 
do 
Aug. 4, 1910 
Aug. 18,1916 
Feb. 23,1917 
do 
Aug. 17,1916 
Aug. 31,1916 
do :... 
do 
do 
do 
Mar. 20,1917 
Mav 2, 1917 
Feb. 30,1917 
Apr. 5,1917 
Oct. 8,1917 
Dec. 8,1917 
Aug. 4, 1916 
Do. 
.do 
do 
....do 
....do 
do 
Crushed leaf tissues 
do 
Mav 8. 1917 
Nov. 19 1917 
Jan. 12, 1918 
do 
Aug. 17,1916 
do 
Do. 
Feb. 15,1917 
Mar. 24,1917 
do 
Mar. 10 1917 
.. .do 
...do 
Apr. 12,1917 
Sept. 23,1916 
Do. 
Sept. 7,1916 
Aug. 15,1916 
Martyn ia louisiana 
Potato 
do 
do.. 
Aug. 16,1915 
Mar. 22,1916 
Aug. 1, 1917 
Pokeweed (Phytolacca de- 
can dr a.) 
Petunia -. 
.do... 
Sept. 30, 1915 
Apr. 10,1916 
Sept. 1,1917 
Do. 
do 
do 
Aug. 5,1917 
do 
do 
Where the crushed tissues of the mosaic plant were used, a frag- 
ment of one of the young leaves was crushed in a sterile dish with 
sterile instruments and small portions of this crushed material in- 
serted in slight incisions made at one or two points in the stem of 
the plant inoculated and other pieces sometimes pricked into the 
young leaves. 
The results of all the inoculations from mosaic cucumber to plants 
outside the cucurbits have been negative, 1 as shown by Table I. 
1 Eecent experiments (1919) indicate that cucumber mosaic may be transmitted to Martynia louisiana 
by moans of aphids taken from mosaic cucumber plants. Inoculations from martynia plants infected in 
this manner have also produced the disease on the cucumber. 
