50 
Research Bulletin No. 1 
CONTACT INOCULATION. 
On March 26, 1910, a severely rotted Early Ohio tuber was 
placed in contact with healthy tubers, Similar experiments were 
made with rotted tubers of the White Ohio potato. It should be 
stated that, in both cases, the healthy tubers employed had an 
unbroken surface. On April 26 the tubers were carefully 
examined and no sign of infection was found in any of the sur- 
rounding healthy tubers of either variety. 
EYE PUNCTURES OF EARLY OHIO. 
Table 10. — A summary of the results of 102 "eye" punctures, in 
all of which some medium was applied with the fungus. 
The greatest amount of rot appeared here on tubers kept at 
the lower temperature and in the highest relative humidity. 
No. of inocu- 
lations 
No. of successful 
inoculations 
Extent of rot 
Temperature 
Humidity 
18 
18 
18 
18 
30 

18 
18 
18 
18 
30 
Slight 
Slight 
1 cm. deep 
1.5 cm. deep 
Slight to f of the 
tuber 
24 to 27° C. 
24 to 27° C. 
8 to 10° C. 
8 to 10° C. 
8 to 10° C. 
Saturated air 
Over CaCl 2 
Over CaCl 2 
Saturated air 
Saturated air 
SURFACE PUNCTURES OF EARLY OHIO. 
Table 11. — Results of 132 surface puncture inoculations , in all 
of which medium was applied. 
No. of 
inoculations 
No. of 
successful 
inoculations 
Extent of rot 
Temperature 
Humidity 
18 
18 
25 to 27 3 G 
Saturated air 
18 
18 
Slight 
25 to 27° C. . . . 
Over CaCL, 
18 
18 
8 to io° a... 
Over CaCl, 
78 
78 
Prominent in 7 
days ; in 4 weeks 
entire tuber 
rotted 
8 to io° a... 
Saturated air 
T 
It will be noted that the rot developed on tubers kept at high 
or low temperatures and at high or low relative humidity. A 
greater amount of rotting occurred at the lower temperature 
with either high or low humidity. 
