AN APPLE ORCHARD SURVEY OF WAYNE COUNTY, NEW YORK. 339 



FIG. 84. Leaf spots probably caused 

 by Phyllosticta sf>. 



hurt the apple had the skin not been 



broken by the scab or by some injury. 



One of these, the pink rot, caused much 



damage in 1902.* 



Treatment. A sufficient number of 



thorough sprayings with the Bordeaux 



mixture will keep the apples prac- 

 tically free from scab. The essential 



points are thoroughness and prompt- 

 ness. Spraying after the scab becomes 



established does little or no good. Some 



men have been surprised to see the 



scab develop under spots where the 



spray was still visible. This simply 



means that the spraying was too late 



the fungus was already in the apple. 

 Since the spores' do not all germinate 



at once, we should not expect one appli- 

 cation of Bordeaux to keep off all the 

 scab any more than we would expect one 

 cultivation of a corn crop to kill all the 

 pigweeds. One application if made at 

 the right time will, however, frequently 

 make a great difference. Three spray- 

 ings at the right times will nearly always 

 keep the apples free from scab. Two 

 will sometimes do so. A further dis- 

 cussion of the method of summer treat- 

 ment and of winter treatment will be 

 found under spraying. (Pages 392 

 to 3940 



Leaf spots caused by the scab fungus. 

 Fig. 83 shows the large blister-like eleva- 

 tions caused by the scab. These spots 

 usually occur on the upper surface, but 

 are not confined to that surface. Late in 

 the season they are nearly black, the color 



FIG. 83. The scab fungus on the 

 leaf. 



'Cornell Bulletin 207. 



