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INSECT AND FUNGOUS ENEMIES OF THE APPLE. 35 
orchards are the most dangerous, but since the spores are like particles 
of dust they may be carried on the wind for several miles. However, 
upon being carried so far they would be scattered over a wide area 
and the chances for serious infection of any one orchard would 
usually be slight, especially since moisture is necessary for the germi- 
nation of the spores after they reach the apple. Orchards with no 
cedar trees within a mile may be considered fairly safe from infec- 
tions. In cleaning up the cedars, the underbrush, fence rows, and 
hedges should be carefully searched 
for young cedars. Little cedar plants 
only a foot high often have cedar 
apples, and these are usually over- 
looked by the orchardist. 
Spraying has not proved entirely 
satisfactery in the control of this 
disease, although much can be accom- 
plished by this method. The usual 
treatment for scab and_leaf-spot, 
namely, spraying (1) just before the 
blossoms open, (2) as soon as the 
petals fall, and (8) three weeks later, 
will largely prevent this disease 
during some seasons. In showery 
weather, however, an extra applica- 
tion should be made about 10 days 
after the petals fall. The sulphur 
sprays appear to be somewhat more 
satisfactory for this disease than the 
copper sprays. 
APPLE LEAF-SPOT. 
With the possible exception of 
cedar rust, leaf-spot, also known as 
frog-eye, is the most important fun- : 
gous disease affecting the foliage of Fic. Bo rage Delay eae enetyeH leaf of 
apple. It occurs in all sections east 
of the Rocky Mountains where the appie is grown and in unsprayed 
orchards causes considerable damage by defoliating the trees. 
The spots are circular or somewhat irregular in outline, and red- 
dish-brown in color, becoming grayish with age. (See fig. 20.) At 
first they appear as minute purple specks, which rapidly enlarge until 
a diameter of from one-eighth to one-half inch is reached. The ma- 
ture spots are usually circular, but after midsummer may become 
irregular or lobed in outline, due apparently to a secondary extension 
492 
