SPRAYING PEACHES. 11 
and the reduction in market value are both considered, it seems evi- 
dent that a loss of 10 per cent of the total value of the peach crop in 
the eastern United States is caused by peach scab. 
THE NATURE AND CAUSE OF THE DISEASE. 
The name commonly applied to this disease is ‘‘peach scab,” but 
it is also known as ‘‘black spot” and ‘‘freckles”’ and in some districts 
it is often improperly called ‘‘mildew.” It is caused by the fungus 
Cladosporium carpophilum Thiim., which grows in the skin of the 
fruit, producing small, circular dark-brown spots. When numerous, 
these spots give the fruit a smutty or blackened appearance and 
‘ause the skin to crack (fig. 2). Fruit badly affected does not reach 
normal size and often drops prematurely. 
The fungus also attacks the twigs, producing brown spots, in which 
it passes the winter. These spots are very common in peach orchards, 
Fia. 3.—Two adult curculios on a young peach. (Considerably enlarged.) 
but they apparently do little damage to the twigs. During the 
spring or early summer the fungus growing in the spots produces 
olive-brown spores which serve to infect the young peaches. Simi- 
lar spores are also produced on the fruit spots. 
THE SUSCEPTIBILITY OF VARIETIES. 
There is a considerable difference in varieties as to their suscepti- 
bility to peach scab. In general, the late varieties are much more 
susceptible than the early varieties. This is due, in part at least, 
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