320 Forestry Quarterly. 



The disease described by W. A. Murrill has 

 Disease become epidemic in parts of New York City, 



of and occurs also in New Jersey, Maryland, 



Chestnut. the District of Columbia, and Virginia. Al- 



though belonging to the genus Diaporthe, 

 the species of which live usually on dead wood, this new species 

 is parasitic. Its life history and effects are thus described: 



"The fungus enters through a wound or dead limb and works 

 beneath the cortex in the layers of the inner bark and cambium. 

 The bark soon dies and changes color, and later becomes rough and 

 warty from the presence of numerous yellowish-brown fruiting 

 pustules, which appear in the lenticels and send out peculiar twisted 

 spore-masses containing millions of minute summer spores. These 

 spores are produced continuously throughout the summer and early 

 autumn, and germinate without a period of rest, when they fall 

 upon wounds in other chestnut trees. The winter spores mature in 

 late autumn in the same pustules, and germinate the following 

 spring, when the mycelium, which has passed the winter in the 

 infested bark, also begins to grow again and continues to spread 

 beneath the cortex, sending up fruiting pustules and distributing 

 spores as in the previous season. 



"The fungus attacks twigs, branches and trunks of Chestnut trees, 

 irrespective of size or position, and usually proceeds in a circle 

 about the affected portion until it is completely girdled. The death 

 of the end of the branch necessarily causes loss of vitality and 

 partial death to the remainder, and this enables the fungus to spread 

 very rapidly through the tissues below until it reaches the main 

 trunk, when the life of the tree is measured by a few years at best." 



Treatment or restriction of this fungus, Mr. Murrill sa^'s, is very 

 difficult. The mycelium cannot be reached by spraying solutions, 

 and the only feasible measure seems to be to cut off infected por- 

 tions and tar or paint the wound against further infection. This, 

 however, is not likely to be effective except with young, vigorous 

 trees, and Mr. Murrill is inclined to think that the disease, when 

 well started, will have to nni its course. 



A New Chestnut Disease. Torreya, September, 1906. p. 186. 



