294 MANUAL OF FRUIT DISEASES 
ScaB 
Caused by Cladosporium carpophilum Thim. 
This disease, known as peach-scab, freckles and black-spot, 
was first described in lower Austria in 1876. Since then it 
has been known commonly in the United States, and it occurs 
to an injurious extent wherever peaches are grown east of the 
Rocky Mountains. It is known also in California and occurs 
to some extent in Canada. 
The damage done by peach-scab is apparently not realized 
by growers, some regarding the disease as a necessary evil, 
scarcely apprehending that their fruit is bringing in the market 
25 per cent less price than clean fruit would command. Some- 
times the disease is mistaken for a peculiarity of the affected 
variety. In spite of these misconceptions many growers do 
appreciate the importance of peach-scab and that it is the 
cause of widespread injury to the peach-crop. There is no decay 
of the fruit, but its market value is lowered ; the size is reduced 
and the fruit dwarfed ; the fruit is sometimes cracked, allowing 
rot-producing organisms to enter the flesh to cause subsequent 
rapid decay. Affected fruits may drop prematurely, and those 
which are picked do not ship well. In some seasons the loss, 
in Indiana for example, has been estimated at ten per cent of 
the crop, while in the eastern United States the loss has been 
put at the same figure. The total annual loss has been placed 
at $1,000,000 in the United States. The growing of certain 
susceptible commercial varieties has been prohibited by this 
disease. Heavy losses occur in West Virginia and western 
Maryland. In Ohio, in 1896, cases are recorded where 20-50 
per cent of the crop was lost, while in New Jersey as much as 
75 per cent of the fruit has been known to be affected in certain 
localities. In central and southern New Jersey the trouble 
is considered by peach-growers as.one of their worst foes, while 
in the hilly portions of the northern part of the state, the disease 
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