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. Kept. 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. Bui. 144 : 116-119. 1909. 

 Brooks, Charles. Some apple diseases and their treatment. Fruit 



spot. New Hampshire Agr. Exp. Sta. Bui. 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. 



