New York AGRICULTURAL EXPERIMENT Station. 403 
spots vary in size from small dots to the large irregular patches 
which are formed when two or more smaller spots coalesce. 
Where the spots are large the fruit may become one sided or oth- 
erwise distorted, and often it cracks open. Yor this reason the 
disease is sometimes called “ the cracking of the apple.” 
On the leaves the fungus has the appearance of a dark mold. 
It is found in spots on both the upper and under surfaces. The 
disease may cause the leaves to be much crumpled and finally 
show brown, dead tissue which breaks away leaving the foliage 
torn and ragged, or the entire leaf may drop off. 
Some varieties are especially susceptible to its attacks, and it is 
not unusual to see a very large proportion of their fruit badly 
cracked by it. On the other hand, there are varieties which are 
generally quite resistant, on which the scab spots increase com- 
paratively slowly, and the cracking of the fruit is seldom or never 
seen. 
On the fallen leaves of the previous season, there develop, in 
the spring, perithecia within which are perfected spores for the 
propagation of the fungus.” The fungus is known to begin its 
‘attacks very early in the season, for occasionally it may develop 
sufficiently to be discovered by the naked eye on unopened blos- 
som buds. In seasons especially favorable to its early develop- 
ment it has been observed to cause great injury early in the sea- 
son, destroying the blossoms and the young fruit. In order to 
control the disease, therefore, it is important to begin treatment 
early. It must be borne in mind that the treatment is effective 
by preventing the germination of the spores rather than by kill- 
ing the fungus after it has become established either on the foliage 
or on the fruit. | 
Treatment.— The scab may be controlled by proper spraying 
with Bordeaux mixture. Fortunately these treatments may be 
combined with others which are advocated by the Entomologist 
2 Aderhold, Dr. Rud. Die Fusicladien unserer Obstbiiume, I. Theil Landw. 
Jahrbiicher, 25: 880-914, 1896. 
