Sept. 15, 1925 
Cladosporium Leaf Mold of Tomato 
531 
end by examination of free-hand sections. As previously stated, in 
all types of fruit symptoms the mycelium, if present, could at least 
be found under the torus scar, and could usually be traced outward 
from that region. This held true in entirety also for the encircling 
collar lesions and the dark furrows, while in the cases of the greenish 
or yellow area on one side and the asymmetrical, lopsided fruits the 
mycelium had not always grown very far from the scar. 
Furthermore, it was discovered by study of free-hand razor sections 
that in all observed types of fruit symptoms the mycelium was 
invariably present in the torus, a fact which is considered highly 
significant. If infection occurred directly through some natural 
'wound in the stem end of the fruit, such as a growth crack or the 
margin of the stem-end scar which is exposed as the enlarging fruit 
bursts the epidermal union between ovary and torus, it would not 
seem that the torus itself would invariably be invaded. 
Not only was the torus infested with mycelium, but frequently certain 
of the sepals were invaded, and the mycelium was usually present 
in the pedicel as far as the first node above 
the torus (fig. 1,N) but not beyond that 
point. In a number of cases carefully 
studied, it was found that the infected 
sepal was directly above the point where 
the fruit invasion had progressed farthest 
from the point of stem attachment, or 
was above the yellowed or stunted side of 
the fruit. In certain cases the mycelium 
in the torus and pedicel occurred only in the 
side towards the infected sepal, or was more 
abundant in that side. In one case where 
there were two adjacent infected sepals, 
the most extensive development of the 
lesion on the fruit was on the same side. 
In the case illustrated by Figure 1 none of the other sepals was 
infected, and this is regarded as an instance of sepal infection and 
subsequent mycelial growth down into the torus and up through 
the cortex of one side of the pedicel to the node. As a rule the 
torus eventually becomes completely permeated with the mycelium 
and the fruit tissue is invaded. The mycelium in the sepal or 
one side of the torus may retard the growth of that side of the fruit. 
In one instance there were five darkened furrows in the fruit, and 
the five sepals above these furrows were infected, the central sepal 
most heavily, while the sixth sepal over the sound side of the fruit 
was not infected. In a case of an apparently normal fruit the 
mycelium in one sepal extended into the upper part of the torus 
cortex at the base of this sepal, and into the cortical parenchyma of 
the pedicel on that side, as shown in Figure 1. No mycelium was 
found in the fruit. , 
In another very similar case the mycelium extended to the base ol 
the torus, and upon removal of the latter a slight darkening was 
visible about the bundles in the scar on the fruit. This fruit was 
incubated at room temperature, and in 10 days an infected zone 
6 mm. broad was visible about the scar. In a third very similar case 
an infected zone 7 mm. broad appeared in 10 days, accompanied by a 
few black subepidermal stripes radiating from the torus scar. 
Fig. 1. — Diagrammatic longitudinal 
section of the pedicel node (N) and 
last internode (P), sepal bases (S), 
torus (T), and stem end of a young 
tomato fruit (F), showing by means 
of the shaded area the distribution of 
the mycelium of Cladosporiumfulvum 
in one case observed. 
