April, 1911.] Occurrence of Apple Blotch in Ohio. 



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formed by the fungus are irregular in shape, varying from a quar- 

 ter of an inch to an inch in diameter. However, they may coalesce 

 and cover a larger portion of the apple. Not until the final stages 

 does the fungus penetrate more than a few millimeters below the 

 epidermis where it gives the infected portion a dry pulpy texture. 



Fig. 1. Apple blotch (Phyllosticta solitaria), showing the nature of 

 the disease. 



Fig. 2. Pycnida of P. solitaria and sunken areas of infected tissue. 



Fig. 3. A group of Smith's cider apples showing the typical blotches. 



Fig. 4. Cankers of P. solitaria on apple twigs. 



At the time the apples are about to be harvested the blotches are 

 most prevalent and at this time the pycnidia begin to appear in 

 the diseased spots below the epidermis (Fig. 2). They are not 

 found in any definite position, but generally they are only seen in 

 the older infected tissue at the center. In the mature pycnidia 

 are found the one-celled, ovoid, hyaline spores varjdng somewhat 

 but usually 9x6 microns. In certain cases we have transverse 

 cracking of the infected areas which is soon followed by a general 

 decav. 



