314 Maine Agricultural Experiment Station. 1917. 



The dry core thus formed is usually proportioned and shaped 

 quite like a thimble. Surrounding the mature core there is a 

 very definite line of demarcation separating the diseased tissue 

 from the healthy. In many cases, by inserting the point of a 

 knife, one may lift out these cores bodily. 



Rhizoctonia mycelium is found in abundance in all stages 

 of dry core formation. Pure cultures have repeatedly been 

 obtained from the inner parts of the diseased areas. Evidence 

 shows that the host cells die and loose their contents, and the 

 walls suberize and are more or less broken down several cells 

 in advance of the fungal filaments. This might lead one to 

 suspect that part of the action is due to a toxin that is secreted 

 by the fungus. 



