490 
Fig. 1. Sooty Blotch of Apple. 
latter numerous minute specks. They 
give the apple a sooty appearance that 
depreciates the market value. The fungus 
growth is entirely on the surface of the 
fruit, and hence the disease is especially 
dependent upon the moist weather for 
development. 
Treatment 
The disease is reddily controlled by 
spraying. Thorough pruning is impor- 
tant, and if light and air have free access 
to the fruit the disease usually gives 
little trouble. 
Sooty Blotch and Fly Speck Fungus. 
Sooty Mould 
Capnodium sp. 
Black sooty fungus sometimes found 
growing upon branches and twigs. Fre- 
quently caused by the deposits of “honey 
dew” from aphids, which is a favorable 
medium for the growth of the fungus. 
Not serious. 
Spray Injury 
Injury from Bordeaux mixture is of 
quite common occurrence. On the leaves 
Fig. 2. 
ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 
it appears first as purplish brown spots 
of various shapes and sizes. They are 
usually smaller, irregular in shape and 
thickly distributed on the affected foliage. 
Soon after the appearance of these spots 
the -leaves may begin to turn yellow. 
Leaves so affected soon fall, and in serious 
cases the trees may be almost entirely 
defoliated. Such extreme cases, how- 
ever, have been very rare. 
On the fruit the injury appears first 
as small, black or brown specks scat- 
tered thickly over the apple. Later in 
the season the skin may become corky 
and russeted. In serious cases the ap- 
ple may be much roughened and deform- 
ed, and large, deeply-sunken scars de- 
velop. The slightly affected fruit may 
almost entirely outgrow its injuries by 
picking time, but when the injury is very 
great the fruit may drop before maturity, 
and in any case is of little commercial 
value. 
The most serious injuries have been ob- 
tained from the early sprayings. This 
may be largely due to the fact that show- 
ers are common at that time of year. It 
is a well-known fact that when an ap- 
plication of Bordeaux is followed by rain 
within the next few days it is likely to 
produce injury. Records from a large 
number of cases of Bordeaux injury would 
indicate that damage seldom, if ever, oc- 
curs in properly sprayed orchards except 
under the above mentioned conditions. 
The injury done by Bordeaux has not 
been great enough to offset the good ac- 
complished, and various commercial grow- 
ers have annually obtained large profits 
from its use, yet the condition has been 
' serious enough to make strong demands 
for a solution of the difficulties. The mat- 
ter has been taken up at various experi- 
ment stations, including those of New 
York,’ Illinois? and New Hampshire, but 
a complete solution of the problem has 
not been found. 
Much trouble may arise from the use 
of improper mixtures and from unsatis- 
1 Hedrick, N. P. Bordeaux Injury. N. 
Agricultural Experiment Station Bulletin ogy. 
1907 
2Crandall, C. S. Bordeaux Mixture. Tl- 
linois Agricultural Experiment Station Bulle- 
tin 135. 1909. 
