438 
more elongated the apple. This elonga- 
tion is seen in apples grown near large 
bodies of water, which lower the temper- 
ature at this season of the year, and in 
seasons when the temperature is low, 
owing to seasonal fluctuations. This in- 
fluence is also seen in the form of apples 
on different parts of the tree. Those in 
the lower north portion are more elon- 
gated than those from the warmer, upper 
south portion. 
The attainment of the highest quality, 
appearance and keeping quality is very 
largely dependent on the warmth and 
length of the growing season. This may 
be measured with a fair degree of satis- 
faction for the apple-growing regions of 
North America by an average of the mean 
temperatures for the months of March to 
September inclusive. This is called the 
mean summer temperature, and gives 
temperatures ranging from 52 to 72 de- 
grees. Factors determining the mean 
summer temperature in a given orchard 
are latitude, elevation, site and aspect, 
soil, culture, prevailing winds and sun- 
shine. 
A summer mean too low for a variety 
will result in greater acidity, increased 
insoluble solids, greater astringency, less 
coloration, decreased . size, scalding in 
storage. 
A summer mean too high for a variety 
results in uneven ripening, premature 
dropping, rotting on the trees, poor keep- 
ing quality, lack of flavor, mealiness, less 
intense color, decreased size. 
The accompanying map (p. 436) shows 
the distribution of the Ben Davis with the 
northern limit of hardiness. 
APPLE DISEASES 
Alternaria Decay 
A decay of apples caused by a species of 
Alternaria was first described from Colo- 
rado by Longyear. This fungus entered 
the apple at the blossom end and pro- 
duced a cob-webby growth of mycelium 
around the seeds. An Alternaria has 
been found a number of times associated 
with apple decays. This fungus usually 
occurs on injured places such as the blos- 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
som end injured by insects or broken 
places in the skin. Associated with other 
fungi this Alternaria torms a rather 
thick, dry covering of mycelium over the 
injured place. The fungus does not usua]- 
ly penetrate very deeply in such cages 
but when ripe apples are inoculated from 
pure cultures, it is found to be capable 
of causing a complete decay. This fungus 
alone has been reisolated a number of 
times from decaying apples which hagq 
been inoculated, thus proving that it 
caused the decay. The apple decay 41. 
ternaria differs sufficiently from a species 
of the same genus which has been found 
repeatedly on dead spots in apple leaves 
and on dead parts of other plants so that 
the two fungi can be distinguished readi- 
ly in culture. The Alternaria from apple 
leaves has not been found to cause de- 
cay of the fruit upon inoculation. 
W. J. Morse 
Apple Tree Anthracnose 
Neofabraea matlicorticis (Cordley) 
Jackson 
H. §. JACKSON 
The apple tree anthracnose is, with 
the possible exception of the apple scab, 
the most serious fungus disease with 
Which apple growers in the Northwest 
have to deal. In general, the disease is 
characterized by the formation of dark 
colored sunken cankers in the bark of 
the younger branches. These are most 
abundant on branches under two or three 
inches in diameter, but are not uncom- 
monly found on branches of larger size. 
When they occur on older branches hav- 
ing a thick bark, the cankers may not 
always penetrate entirely to the wood. 
Usually, however, the bark in the mature 
cankers is found to be entirely dead, the 
cambium destroyed and the sap wood dis- 
colored to a limited extent. 
Development of the Cankers 
By close observation one may find the 
young cankers beginning to develop 
commonly early in November. It is 
possible that in seasons of early fall rain 
they may begin to appear much earlier. 
They begin their development as small 
reddish brown spots in the bark. These 
