May 12,1923 
Rhizopus Responsible for Sweet Potato Decay 
451 
Tabi^e Y.—^rganisms isolated from subset potatoes inoculated with Rhizopus ariocarpi or 
with a mixed spore suspension of Rhizopus artocarpi and Rhizopus nigricans, or not 
inoculated and held as controls 
Inoculated with Rhizopus artocarpi. 
Inoculated with 
Rhizopus arto¬ 
Control. 
Washed before inoculation. 
Unwashed. 
carpi and Rhizo¬ 
pus nigricans 
(potatoes 
washed). 
Washed. 
Un¬ 
washed. 
Tempera¬ 
ture. 
Rhizo¬ 
pus 
arto¬ 
carpi. 
Rhizo¬ 
pus 
nigri¬ 
cans. 
Rhizo¬ 
pus 
artocarpi 
and 
Rhizo¬ 
pus 
nigri¬ 
cans. 
(mixed). 
Rhizo¬ 
pus 
arto¬ 
carpi. 
Rhizo¬ 
pus 
nigri¬ 
cans. 
Rhizo¬ 
pus 
artocarpi 
and 
Rhizo¬ 
pus 
nigri¬ 
cans. 
mixed. 
Rhizo¬ 
pus 
nigri¬ 
cans. 
Rhizo¬ 
pus 
tritici 
and 
Rhizo¬ 
pus 
nigri¬ 
cans. 
Rhizo¬ 
pus 
nigri¬ 
cans. 
Rhizo¬ 
pus 
nigri¬ 
cans. 
*C. 
X4 . 
II 
II 
3 
i6 
9 
2 
X3 
2 R.t 
16 
16 
12. 
9 
16 
I 
7 
26 
16 
and R.n 
and 
2 R.t. 
IS 
17 
Tabi^K VI .—Organisms isolated from sweet potatoes inoculated with Rhizopus reflexus or 
with a mixed spore suspension of Rhizopus reflexus and Rhizopus nigricans, or not 
inoculated and held as controls. 
Inoculated with Rhizopus reflexus. 
Inoculated with 
Rhizopus reflexus 
and Rhizopus 
nigricans. 
Control. 
Tempera¬ 
ture. 
Washed before inoculation. 
Unwashed. 
Washed. 
Un¬ 
washed. 
Washed. 
Un- 
washed. 
Rhizo¬ 
pus 
reflexus. 
Rhizo¬ 
pus 
nigri¬ 
cans. 
Rhizo¬ 
pus 
reflexus 
and 
Rhizo¬ 
pus 
nigri¬ 
cans 
(mixed). 
Rhizo¬ 
pus 
reflexus. 
Rhizo¬ 
pus 
nigri¬ 
cans. 
Rhbo- 
pus 
reflexus 
and 
Rhizo¬ 
pus 
nigri¬ 
cans 
mixed. 
Rhizo¬ 
pus 
nigri¬ 
cans. 
Rhizo¬ 
pus 
nigri¬ 
cans. 
Rhizo¬ 
pus 
nigri¬ 
cans. 
Rhizo¬ 
pus 
nigri¬ 
cans. 
•c. 
14. 
12 
17 
0 
10 
16 
2 
22 
IS 
14 
17 
12. 
17 
14 
2 
16 
IS 
I 
8 
IS 
12 
30 
This species caused no infection, however, when R. nigricans was 
included in the inoculum. Washing the potatoes did not influence the 
results. These results indicate that R. reflexus probably is not normally 
a factor in the decay of potatoes at storage temperatures. 
The results recorded in Table VII show that R. oryzae ® falls into the 
same group as R. tritici with regard to the amount of infection at these 
temperatures. The only infection that took place was when the potatoes 
were washed. This fact may have had no relation to washing and may 
have been accidental, for in the cases of R. artocarpi and R. reflexus, 
washing had no effect upon the amount of infection. The effects of 
® It is assumed for two reasons that R. oryzae was the organism that caused the infection, first, because such 
a highly concentrated spore suspension was used in the inoculation of the potatoes, second, because R. 
trUici or the other species belonging to this group never have been known to cause infection when it was not 
used in the inoculum, except in the one instance shown in Table V in the case of R. trUici. 
