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APPLE LEAF-SPOT OR BLACK ROT CANKER. 



P. L Bryce, Macdonald College, F.Q. 



This disease, Spaeropsis malorum, known to many as the New York 

 Apple Tree Canker, has been noted at Ste. Annes in two forms. First 

 may be mentioned the Apple Leaf Spot, Brown Spot, or Frog-eye. On 

 the upper surface of the leaves appear light brown spots with a sharply 

 marked darker rim. The outline is circular, with a depressed Hght brown 



Apple leaf affected with Apple Leaf-spot fungus 



part of the spot near the centre, while the centre itself is lightly raised- 

 The spots measure 1-8 to 1-2 inch across. The areas appear in early 

 spring as purple flecks, and while yellow in early summer, their colour 

 later becomes grayish. Infection of leaves takes place continuously 

 throughout the growing season by spores shed from the "body" or branch 

 cankers of the disease. 



