222 ILLINOIS ACADEMY OF SCIENCE 
(Plate I, Fig. 8): The width is about the same as that of the 
mycelium. The septations are often more numerous than in 
the mycelium. 
MYCELIUM 
The mycelium is dark colored when well developed, but light 
when young. It varies from 3 to 9 microns in width. The 
mycelium is light colored, much finer, the septations are fur- 
ther apart, and little nodules often appear at various intervals. 
LITERATURE 
There are only a few references in literature to Alternaria 
as an enemy of the apple. Morse’ mentions the leaves as being 
attacked. Stakman and Rose of Minnesota describe an Al- 
ternaria on the fruit of the Wealthy apple. It causes a small 
brown spot in some ways resembling those above described. 
Personal communication with these authors, however, proved 
it to be different. The spot they describe is much smaller, dif- 
ferent color, and has a more regular outline. They were able 
to produce typical spots when the organism was inoculated on 
the fruit, which I have not been able to accomplish. 
Longyear’ of Colorado has found Alternaria causing a blos- 
som and core rot which enters in the stamens and stigmas and 
usually occurs in storage. These are both soft rots. Cook 
and Martin* found Alternaria in the Jonathan spot, and con- 
sider it to be the cause. They produced typical spots with the 
organism. However, Scott’ considers that the Jonathan spot is 
due possibly to arsenical poisons, and Norton’ ascribes it to 
gases from the cooling plants. Brooks, Fisher and Cooley’ 
found Alternaria in apples in storage. 
There is a marked resemblance between this spot as here 
described and that attributed to Lime Sulphur as described 
by the Illinois Experiment Station (Bulletin 185). Communi- 
cation with the man from whose orchard the fruit came proved 
that no spray had been used later than two weeks after the 
petals fell. According to the Illinois Bulletin, no injury is 
done to the fruit by Lime Sulphur before July. This would 
indicate that this spot is not caused by Lime Sulphur. 
It is possible that all these diseases, including the one de- 
scribed, are caused by the same organism, a variety of A. 
