60 
BULLETIN 879, U. S. DEPARTMENT OF AGRICULTURE. 
MICRAMPELIS LOBATA AS A SOURCE OF EARLY INFECTION. 
As has already been stated, there are two wild species of the Cu- 
curbitaceaB which are native in the Middle West. These are Mi- 
crampelis lobata and Sicyos angulatus. The latter does not occur as 
commonly in Michigan and Wisconsin as Micrampelis lobata, which 
is found in many localities where cucumbers are grown, either wild * 
or used as an ornamental vine. Observations in Michigan showed 
that the micrampelis was subject to a mosaic disease similar to that 
on cucumber, cases being observed during 1915 and 1916 by Dr. 
E. A. Bessey, Mr. W. W. Gilbert, and the writer. Inoculations 
made from mosaic cucumber to healthy plants of micrampelis in the 
spring of 1917 resulted in typical cases of mosaic, and reciprocal 
inoculations from mosaic micrampelis to cucumber were equally 
successful, as shown in Table XX, thus proving the identity of the 
two diseases. 
Table XX. — Results of cross-inoculations from mosaic cucumber plants to healthy plants \ 
of Micrampelis lobata and from mosaic micrampelis to healthy cucumber plants. 
Inoculations from Mosaic Cucumber Plants to Healthy Plants of Micrampelis. 
Date inocu- 
lated. 
Treatment. 
Inoculum. 
Source of infection. 
Num- 
ber of 
plants 
inocu- 
lated. 
Results. 
Num- 
ber of 
mosaic 
plants. 
Date ob- 
served. 
May 11, 1917.. 
Do 
May 16,1917 
Do 
May 24,1917 
Do 
June 20,1917 
Do 
Aug. 31,1917 
Sept. 3, 1917 
Do 
Inoculated . . 
Control 
Inoculated . . 
Control 
Inoculated . . 
Control 
Inoculated . . 
Control 
Inoculated . . 
do.. 
Control . 
Crushed tissue of mosaic 
leaf. 
Crushed tissue of healthy 
leaf. 
Crushed tissue of mosaic 
leaf. 
Crushed tissue of healthv 
leaf. 
Crushed tissue of mosaic 
leaf. 
Crushed tissue of healthy 
leaf. 
Crushed tissue of mosaic 
leaf. 
Crushed tissue of heal th y 
leaf. 
Crushed tissue of mosaic 
leaf. 
do 
Crushed tissue of healthv 
leaf. 
Artificial infection. 
Artificial infection. 
Artificial infection 
Artificial infection 
Natural infection. 
do 
May 22,1917 
Do. 
May 29,1917 
Do. 
June 10,1917 
Do. ^ 
July 3, 1917 
Do. 
Sept. 10,1917 
Sept. 12,1917 
Do. 
Inoculations from Mosaic Micrampelis Plants to Healthy Cucumber Plants. 
May 24,1917 
Do 
July 3, 1917 
Do 
Oct. 8, 1917 
Do 
Oct. 30,1917 
Do 
Inoculated . . . 
Control 
Inoculated... 
Control 
Inoculated... 
Control 
Inoculated . . . 
Control 
Crushed tissue of mosaic 
leaf. 
Crushed tissue of healthy 
leaf. 
Crushed tissue of mosaic 
leaf. 
Crushed tissue of healthy 
leaf. 
Crushed tissue of mosaic 
leaf. 
Crushed tissue of heal tin- 
leaf. 
Expressed juice of mo- 
saic plant. 
Expressed juice of 
healthy plant. 
Inoculated from 
mosaic cucum- 
ber plant. 
10 
10 
8 
7 
6 
6 
10 
8 
9 

6 

2 

7 

Natural infection.. 
Natural infection.. 
Natural infection. 
June 9, 1917 
Do. 
July 15,1917 
Do. 
Oct. 14,1917 
Oct. 20,1917 
Nov. 10,1917 
Do. 
