CHAPTER XXIV 



LOCUST DISEASES 



The native species of locust are unimportant forest-trees. 

 The common locust of eastern United States {Robinia Pseudch 

 cacia) was more frequently used as an ornamental in previous 

 years than at present. Insect damage has made the tree 

 difficult to grow. The only fungous diseases of the locust that 

 have considerable importance are the yellow and brown checked 

 wood-rots. The yellow wood-rot is caused by a fungus that 

 grows only in the wood of the locust. This rot is common in 

 ornamental trees and often causes their death. 



Yellow Wood-Rot 

 Caused by Fames rimosus Berkeley 



The yellow wood-rot of the trunk and branches of the locust 

 is common throughout the range of this tree. Young trees 

 less than six inches in diameter are rarely affected. 



Symptoms. 



The central portion of the heartwood is reduced to a soft 

 yellow spongy mass for several feet up and down the trunk or 

 limb. From this central decayed area, as seen in cross-section, 

 several V-shaped bands reach out radially toward the sapwood. 

 When the wood is split lengthwise, these bands of decay are 

 seen to be one or two inches wide. At the center of each band 

 is a small reddish core and extending upward and downward 

 from this core the partially decayed wood varies from orange- 



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