Sept. 15, 1925 
Gladosporium Leaf Mold of Tomato 
533 
In a number of the cases of sepal inoculation the fruit became lop¬ 
sided, with the atrophied side usually longitudinally furrowed and 
slightly yellowish. In four cases the atrophied side was under the 
sepals which first exhibited Cladosporium sporulation and which 
were most likely the particular sepals originally infected as a result 
of the inoculation. In one case the fungus was sporulating on three 
adjacent sepals, and the side of the fruit under these sepals was 
atrophied and was traversed by a longitudinal furrow under each 
of the three sepals. Upon sectioning, however, no mycelium was 
found in the fruit nor the torus but was found only in these three 
sepals just mentioned. Somewhat similar cases have herein been 
described previously in connection with torus infection and lopsided 
fruits. Therefore it seems probable that the presence of the fungus 
in the sepal may have an injurious effect upon the corresponding 
sector of the fruit. 
In six cases the mycelium was found in the cortical tissues of the 
last internode of the pedicel (fig. 1, P), but never above the first node 
above the torus (fig. 1, N), a condition previously noted in connection 
with pedicel infection. This indicates that the mycelium is unable 
to pass through this node. As the fungus is strictly intercellular 
and readily invades the fruit from the torus, it seems likely that the 
intercellular spaces are continuous throughout the sepals, last pedicel 
internode, torus, and fruit; while the failure of the fungus to pass 
upward beyond the first pedicel node would seem to indicate that 
the intercellular spaces were not continuous through that node. 
Owing to the absence of stomata in the fruit, the continuity of the 
intercellulars of the sepals and the fruit tissue may be of some physi¬ 
ological significance. 
Observations made in a greenhouse crop in August, 1924, about 
the time the lowest clusters of fruit were mature, gave further evi¬ 
dence that fruit invasion results from sepal infection. Leaf mold 
was extremely severe on the foliage; and while no black stem-end 
rot was found, very abundant sepal infection (pi. 3, D) had occurred 
as was evidenced by the sporulation of the fungus on the sepals. 
The prevalence of sepal infection was determined by an examination 
of a large number ox calyces in the lower five or six clusters. (See 
Table I) 
Table I. — Prevalence of calyx infection in greenhouse tomatoes 
Number 
Total 
Percentage infected on— 
« 
* 
calyces 
examined 
per cent 
infected 
1 se¬ 
pal 
2 86- 
pals 
3 se¬ 
pals 
4 se¬ 
pals 
5 se¬ 
pals 
6 se¬ 
pals 
Ovaries less than 1 cm. diameter__ 
243 
52 
34 
12 
4 
1 
0.4 
Fruits more than 1 cm. diameter,..._ 
294 
80 
36 
20 
16 
5 
3 
0.3 
A very high percentage of the calyces were visibly infected, even 
in the case of small ovaries, and in many instances more than one 
sepal was infected. In view of the two to three weeks of incubation 
between infection and sporulation, it would appear that much of 
this infection had occurred during the blossoming peiiod; and it prob¬ 
ably is this early infection which is most likely to give the fungus time 
to grow down into the fruit before the latter ripens and is picked. 
66850—25f-3 
