DISEASES INJURIOUS TO FRUITS. 77 



winter . spores are produced on the branches in canker spots 

 from which come the new sources of spring infection. 



Remedies. Remove and burn all canker spots found on 

 the trees each year, as these are the sources of infection. De- 

 stroy the diseased fruit. Spraying with Bordeaux mixture and 

 later, when the fruit begins to ripen, with a copper carbonate 

 solution will hold the disease in check. 



Black Rot (Sphaeropsis malorum) 

 is a common source of trouble. It 

 especially attacks the summer ap- 

 ples at the time of ripening and 

 the other kinds in storage. This 

 fungus also occurs on the branches 

 and leaves of apples. 



Remedies are the same as for 

 Bitter Rot. 



Root Galls, in the shape of 

 roundish swellings, are sometimes 

 found on the roots of apples and 

 other trees. Stocks thus affected 

 should be regarded with suspicion, 

 although some of these galls do 

 not appear to be seriously injurious. 

 Leaf Rust (Gymnosporangium 

 macropus) and (G. globosum). 

 This disease causes serious injury 

 to the foliage of apples and pears 

 so that the foliage and fruit crops 

 are destroyed. This fungus causes 

 yellow blotches on the leaves, and 

 later, cluster cups with thorn-like 

 tops appear on the under side of 

 the leaves. One stage of this dis- 

 ease lives on the Red Cedar, where 

 it produces Cedar apples from 



Fig. 30.-Bltter rot of ap- whlch in the Spring COme a brlght 

 pie. Branch infested scarlet, gelatinous, honey-like 

 with canker of bitter masSS> The sporeg from ^ Re(J 



