CHERRY DISEASES 183 



for several years. Finally an affected branch or trunk may be 

 girdled, as a result of which the foliage becomes yellow, then 

 brown, and finally withers and dies. Such foliage hangs on the 

 tree for some time. Below a girdled trunk, suckers may spring 

 up from the healthy part. 



In addition to the cankers just described another phase of 

 bacterial-gummosis is found in a blighting of the spurs and 

 buds. The first indication of this is usually not noticed until 



FIG. 50. Cherry twigs affected with bacterial-gummosis ; cankers 

 about the base of blighted spurs. Gum-flow evident. 



spring, when some of the buds fail to swell and open when others 

 unfold. A drop of gum often exudes from such buds. Some- 

 times affected buds do unfold in the spring in an apparently 

 normal fashion, but before the blossoms open, these buds wilt 

 and become dry. 



Cause. 



The bacterial-gummosis of cherry is caused by Bacterium 

 Cerasi. Before proceeding with a discussion of this particular 

 disease, brief reference will be made to the causal nature of 

 gummosis in general. As already indicated, the trouble may be 



