APPLE DISEASES 
The disease 18 too common to 
need a detailed description. It seems to 
pe very variable in appearance The most 
common condition is the occurience of 
sunken areas one-eighth to one-half inch 
in diameter, which have somewhat the 
appearance of bruises on the surface of 
the apple. (See Fig. 1.) In the early 
stages the skin is perfectly normal in 
color, though often retaining the green 
tint longer than the surrounding tissue. 
In red apples the spots may be deeper in 
color for a time than the surrounding tis- 
sue. Later they gradually turn brown. 
The skin is usually unbroken in both 
early and late stages. 
In cutting an affected apple one finds 
a browning of the tissue just underneath 
the sunken areas on the surface and simi- 
lar discolorations are also frequently 
found scattered through the substance of 
the fruit. A close examination shows 
these discolorations are not entirely sep- 
arated but are associated with the vas- 
cular system of the fruit, and connected 
with each other by very fine brown 
strands of diseased tissue. These internal 
spots are usually more abundant near 
the surface of the apple and in most vari- 
eties are found more numerous toward 
the blossom end. A larger amount of 
starch is usually found in the diseased 
cells than in the surrounding tissue. 
Africa. 
Cause 
Unlike most other diseases the fruit pit 
is presumably not caused by any organ- 
ism: at least, no fungi or bacteria have 
been found associated with these spots. 
It evidently belongs to a class of so-called 
physiological diseases. Various explana- 
tions have been offered by investigators 
as to the reasons for the formation of 
the spots of diseased tissue. Among these 
explanations given by various authorities 
are the following: Acidity of cell sap fol- 
lowing excessive transpiration; prema- 
ture ripening; abundant moisture and 
high temperature; influence of stock on 
scion; dry weather before maturity; 
complete fertilizers; bursting of cells 
from pressure due to lack of balance be- 
tween moisture supply and transpiration. 
467 
In the Northwest the disease is found 
on soils so diverse both as regards char- 
acter and richness, and varies so greatly 
in abundance and severity between differ- 
ent seasons, that the writer is led to the 
conclusion, on present evidence, that the 
most important factois influencing its 
presence from season to season, are cer- 
tain varying factors of climate which in- 
duce the disease by acting through their 
effect upon the balance existing between 
the moisture content of the soil, the rate 
of absorption by the roots and the amount 
of evaporation from foliage and fruit. 
A trouble of the apple also very com- 
mon in the Northwest usually referred to 
as core rot 1s characterized by a prema- 
ture breaking down of the tissues, start- 
ing at the core. This is believed by the 
writer to be closely related in cause to the 
fruit pit and the factors influencing its 
presence are considered similar. It must 
be recognized that among the different 
varieties of apples the inherent differ- 
ences in adaptability to certain types of 
environment and the natural differences 
in the texture of the fruit gives rise to 
great differences in susceptibility to such 
troubles. 
Growers should be cautioned against 
mistaking the fruit pit for the “fruit 
spot,” prevalent in the Eastern United 
States and particularly in New England, 
which has long been confused with the 
former. This fruit spot is caused by a 
fungus known as Cylundrosporsum pom, 
and can be prevented by spraying, a 
method which is useless in controlling 
the fruit pit. So far as we know, the 
fruit spot does not occur in Oregon. 
Fruit Rot 
Coniothyriose 
The rotten spot is circular in uniform 
tissue, brownish, about the color of the 
common soft rot, and due to loss from 
evaporation, the tissue shrinks as the 
spot ages, leaving the surface much 
wrinkled. Distributed somewhat sparsely 
and irregularly over the spot are the 
fruiting cavities of the fungus. In rotten 
spots, produced by inoculation, these 
cavities frequently assume a somewhat 
