90 MANUAL OF FRUIT DISEASES 
tube of the fungus rapidly develops a system of mycelium ; the 
threads grow between the cells of the fruit. The large flesh- 
cells react against the invasion by the fungus as evidenced 
by their thickened walls. Within the center of such an affected 
region a small pocket is produced by the collapse of one or two 
cells. The rate of spreading varies with the variety. After 
the fungus is well established within the fruit, mycelial masses 
are developed beneath the epidermis. Ultimately these break 
through the protective layer and expose themselves as cup- 
shaped fruiting structures within which conidia are produced. 
Sometimes pycnidia are developed on affected areas; in these 
are formed pycnospores which assist in disseminating the fungus. 
Control. 
This apple fruit-spot is readily controlled by the use of fungi- 
cides. Two applications give satisfactory results: the first 
should be made about the last of June and a subsequent appli- 
cation should be made as late as the middle of July. Earlier 
and later applications as a rule have little value, while those 
made early in July are very efficient. If spraying or dusting for 
apple-scab is practiced, the second and third applications for 
the scab disease will suffice for fruit-spot. These applications 
are made (1) when about two-thirds of the petals have fallen 
and (2) about three weeks later. 
REFERENCES 
Brooks, Charles. The fruit spot of apples. New Hampshire Agr. 
Exp. Sta. Rept. 19-20: 332-365. (Also published in Bulletin 
Torr. Bot. Club 36 : 423-456.) 1908. 
Brooks, Charles. Some apple diseases. The fruit spot of apples. 
New Hampshire Agr. Exp. Sta. Bul. 144: 116-119. 1909. 
Brooks, Charles. Some apple diseases and their treatment. Fruit 
spot. New Hampshire Agr. Exp. Sta. Bul. 157: 10-13. 1912. 
Brooks, Charles and Black, C. A. Apple fruit spot and quince blotch. 
Phytopath. 2: 63-72. 1912. 
Clinton, G. P. Report of the station botanist. Apple fruit spot. 
Connecticut Agr. Exp. Sta. Rept. 1909-1910 : 723-724. 1911. 
