294 MANUAL OF FRUIT DISEASES 



SCAB 

 Caused by Cladosporium carpophilum Thiim. 



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 



