532 
Journal of Agricultural Research 
Vol. XXXI, No. 6 
These observations indicated that beyond doubt there was a 
correlation between the stem-end fruit invasion and the presence 
of the mycelium in the sepals, torus, and pedicel, and that the latter 
condition bore a causative relation to the former. The presence of 
stomata in the sepals, torus, and pedicel would readily permit spore 
infection, and it would seem very likely in the cases just cited that 
infection had occurred in the sepal, the mycelium proceeding from 
the sepal down into the torus and thence up into the pedicel and down 
into the fruit. In other cases examined no mycelium was seen in 
the sepals, indicating that spore infection probably took place on 
the torus or pedicel, both of which bear stomata. Apparently the 
mycelium can not pass the pedicel node (fig. 1, N), so infection, to 
reach the fruit, probably must occur below the first pedicel node above 
the torus. 
Fourteen of the lopsided fruits, including some remaining green 
or yellow on the atrophied side and some showing the color retarda¬ 
tion without any marked asymmetry of shape, were searched for 
mycelium, and in all but three cases a little was found directly under 
the stem-end scar. The torus was present on six, and in every case 
it contained mycelium. In freshly picked specimens, the mycelium 
was found in the atrophied or yellowed side of the fruit, and ordi¬ 
narily was scanty, seldom permeating any considerable proportion 
of the affected side. Therefore, it would seem very likely that the 
lopsidedness and yellowing of such fruits was attributable to the 
early presence of the mycelium in the torus or pedicel, the region 
through which the water and food materials for the fruit must pass. 
However, the fungus does not seem to kill the tissues in the torus and 
pedicel. 
These observations suggested that fruit invasion was probably the 
result of very early spore infection of the sepals, pedicel, or torus. 
To test this theory, a number of inflorescences were inoculated, in 
the greenhouse in March, by placing a loopful of a spore suspension 
on the uninjured pedicel, torus, sepals, or stigma. In practically 
no cases had the ovary more than barely begun to enlarge, and, in 
the cases of pedicel, torus, and sepal inoculation, these organs were 
first sprayed with distilled water before the spore suspension was 
applied. In 9 out of 37 cases of sepal inoculation, ana 2 out of 6 
cases of blossom inoculation on the last intemode of the pedicel, the 
fungus was found sporulating on the sepals within three to five weeks. 
An examination of razor sections of the stem end of the fruit 8 
to 10 weeks after inoculation showed the typical intercellular Clado- 
sporium mycelium in 5 of the 37 cases of sepal inoculation, 1 of 
the 4 cases of torus inoculation, and in 2 of the 6 cases in which the 
last internode of the pedicel was inoculated. No invasion occurred 
in the 4 cases in which the next to the last internode of the pedicel 
was inoculated, nor in the 5 cases of stigma inoculation. The identity 
of the mycelium within the fruits was proved by tissue transfers to 
agar. It was rather surprising to find certain fruits completely 
infested with the intercellular mycelium and yet showing no con¬ 
spicuous discoloration of the tissues. In one case of sepal inocula¬ 
tion a typical, dark, stem-end rot of the fruit was noted 14 weeks 
after inoculation. These tests prove that fruit invasion may 
result from very early spore infection of the sepals, torus, or last 
pedicel internode. 
