APPLE DISEASES 



47 



King are sometimes so grouped. A peculiar and interesting 

 case was called to the authors' attention in a New York State 

 orchard where old trees of the Baldwin variety had been 

 grafted to Twenty Ounce some twenty years ago. The point of 

 union is about midway distant between the crotch and the 

 highest tip of the branches. The canker shows abundantly 

 on the Twenty Ounce portions of the tree, but the Baldwin stock 

 is entirely free from the disease. In most cases the disease 

 extends down the Twenty Ounce bark to the point of union, 

 there stopping very abruptly. This indicates that the Bald- 

 win is at least not to be classed with the Twenty Ounce and 

 others of the most susceptible kinds. In Ontario, Canada, 



, 



FIG. 10. Early stages in the development of black-rot of apple. 



the Ben Davis and Northern Spy are said to be susceptible 

 varieties. 



Symptoms. 



Ripe fruits are more commonly attacked than green fruits. 

 Signs of the disease may show anywhere on the surface or at the 



