A New Apple Rot. 
11 
the case of the apple, that the fungus gains a foothold on the with¬ 
ered stamens and stigmas which remain in the blossom end of the 
fruit. This may quite often occur early in the season soon after 
the flowering period and while the fruit is just forming. For, 
when the withered stamens and stigmas are placed in a moist cham¬ 
ber, at this time, the Alternaria frequently develops. The 
rotting effects of the disease, however, do not usually appear until 
after the growing period is nearly past and when the ripening stage 
is reached. Thus it would appear that the fungus is not capable of 
making much headway while the tissues are in a young, growing 
condition and when the vital processes are most active, but behaves 
more in the nature of a ripe rot fungus and is, therefore, not 
strictly parasitic. This is also suggested from the fact that young- 
growing apples when inoculated with the fungus were not much 
affected by it. 
The principal source of infection in spring appears to be the 
diseased fruits of last year, which remain in the orchard in a shriv¬ 
elled and blackened condition, either lying on the ground, or some¬ 
times left clinging to the fruit spurs. Young fruit which has failed 
to develop fully, perhaps due to imperfect pollination, is frequently 
found to be permeated with this fungus, after having withered 
upon the tree. In such cases the fungous threads within the tissues 
of these mummified fruits are capable of producing a crop of spores 
when the conditions are favorable the following spring. Some of 
these old diseased parts, when placed in a moist chamber, gave rise 
to a vigorous growth of conidia-bearing threads, the spores of which 
started the rot when used in making inoculations. The fungus 
evidently hibernates also on the twigs and fruit spurs, as it was ob¬ 
tained from them during the winter season. Wounds in the fruit 
caused by the larvae of the codling moth frequently give entrance 
to the Alternaria. (Plate III). 
ARTIFICIAL CULTURES AND INOCULATIONS. 
Numerous cultures of the fungus have been made in the labora¬ 
tory, using several different culture media. From these, inoculations 
of sound, ripe fruit were performed by inserting the spores of the 
fungus into punctures made with a sterilized needle. Usually in two 
or three days the point inoculated begins to show a surrounding 
area of decaying tissue, which widens rather slowly but steadily 
until the entire fruit is involved. The only fruit besides the pear 
and apple that has been inoculated with this fungus is the tomato, 
but in such cases it made almost no progress. (Plate I). 
varieties affected and extent of injury. 
In the case of the apple the varieties reported as most com¬ 
monly subject to the Alternaria rot are the Lawver, Foy, Mann, 
