APPLE DISEASES 
project from the tumor itself. The in- 
terior of the tumor is white. 
It is not known what other leguminous 
crops are susceptible to crown gall. It 
is believed, however, that there is reason 
to suspect all of the clovers. 
(See Circular 76, Bureau of Plant In- 
dustry.) 
*Cylindrosporioum Fruit Spot 
Cylindrosporium pomi. Brooks 
Qceurrenece and Symptoms 
The disease is of common occurrence in 
New England and is found in New York, 
Michigan, Ontario, and probably in other 
sections of the United States and Canada. 
The Baldwin is especially susceptible, but 
nearly every New England variety is 
more or less affected. 
The disease appears about the middle 
of August as minute spots or specks on 
the surface of the apple. At first these 
are indicated merely by a deeper red 
eolor of the skin, if situated upon the 
colored part of the fruit, or by a green 
color, if situated upon the lighter portion. 
As the apple ripens the spots enlarge and 
many of them become brown and sunk- 
en, giving the fruit an unsightly appear- 
ance which often greatly depreciates its 
market value. The tissue beneath the 
spots is dry and brown. 
The Fungus 
The first studies upon this disease seem- 
ed to indicate that it was not produced 
by a fungus, but recent studies have dem- 
onstrated the causal relation of a fungus 
which seems to be properly a species of 
Cylindrosporium, as the title suggests. 
Infection probably takes place in July 
or August when the stomata are being 
torn open and the protecting layers of the 
lenticles are not yet formed, a season 
when the metabolism of the apple is ex- 
tremely great and the _ transpiration 
stream necessarily large. 
Control 
The disease is readily controlled by 
spraying with Bordeaux, and weaker fun- 
gicides are often very effective. Sprayings 
* see Duggar, Fungus Diseases of Plants, p. 
465 
made as late as July have been found to 
entirely prevent the disease. 
CHABLES BROOKS 
CoLtLtaR Ror. See Sun Scald. 
Coryneum or Orange Leaf Spot 
Coryneum follicolum 
Has a central, erumpent pustule with an 
immediate border of orange yellow; this 
yellow area shades off into dark color 
toward the green tissue Hartley has re- 
ported, upon investigations of the fungus 
in this case, that it is not actively 
parasitic. Possibly we have this fungus 
following something else, after the man- 
ner that another fungus follows the black- 
rot leaf spot. 
See Rust of Apple. A. D. SEewpy, 
Wooster, Ohio. 
Dix Back. See Rosette. 
Dropping of Apple Leaves 
Many leaves drop from apple trees’ in 
summer and cause anxiety to fruit grow- 
ers. Probably the three most important 
reasons why the leaves drop are: First, 
that the tree may regain a proper balance 
between top and root. There is often a 
great leaf development, owing to moist 
conditions, and when drier weather comes, 
there are too many leaves for the tree to 
support, hence some of them drop off. 
second, that under certain conditions, 
especially when there has been a wet sea- 
son, leaves will scald and drop off. Spray- 
ing sometimes causes this scalding. Third, 
that the leaves are affected with a leaf 
spot disease. The development of this 
disease may, however, come after they 
become weak from lack of moisture to 
support them, or when the leaf is weak- 
ened by sun scald. Asa rule, under good 
cultivation, there are quite sufficient 
leaves left to develop the fruit properly. 
Dry Rot 
This is a disease which affects the 
fruit and is indicated on the exterior of 
the apple by small circular depressions. 
When the skin is removed, dryish, brown 
tissue is found at the diseased spots, and 
when the fruit is badly affected, this 
brown and pithy condition may be seen 
extending through much of the fruit. The 
