306 MANUAL OF FRUIT DISEASES 
REFERENCES ON Peacu-GUMMOSIS 
Cesar, L. Peach diseases. Cankers and gumming of peach trees. 
Ontario Agr. Dept: Bul: 201: 38-40. 1912. 
Selby, A. D. Preliminary report upon diseases of the peach. 3. A 
twig disease with gum-flow. Ohio Agr. Exp. Sta. Bul. 92:199- 
206. 1898. 
Taft, L. R. Spraying calendar for 1898. Gum-disease of the peach. 
Michigan Agr. Exp. Sta. Bul. 155: 304. 1898. 
BLACK-SPOT 
Caused by Bacterium Pruni E. F. Smith 
This peach trouble is known only in the eastern and central 
United States; so far it has not been reported in any other 
region of the globe. Not only is its range limited but its 
history is rather brief, and its importance has prompted scien- 
tific writings only during the past decade. But in the short 
history of black-spot, or shot-hole as it is frequently called, it 
has assumed a very prominent réle in the culture of stone-fruits 
in the humid regions of the South. It is less important in 
the North and East. In Missouri it is rated as one of the worst 
of fruit diseases. The losses induced by the black-spot patho- 
gene are not easily reckoned. But in Missouri it has been 
found that from 1 to 10 per cent of the Elberta peach fruits 
is injured in well cared for orchards, and from 25 to 75 per 
cent in poorly managed orchards. All affected fruits are 
graded second class. Furthermore, such fruits do not ship well, 
often being completely rotted in transit as a result of rot-fungi 
which gain entrance through black-spot lesions. The injury 
is not confined to the fruit alone, but foliage is attacked. Dis- 
eased foliage is less efficient than healthy leaves, and so the 
vitality of the tree suffers. This also results, in the event of 
early spring infection, in the reduction in size and quality of 
the fruit. Severe leaf-injury also results in a reduction in 
the vitality of the fruit-buds and even prevents the formation 
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