Ill 



THE CHESTNUT CANKER 



By William A. Murrill 



Nearly two years have elapsed since I gave the readers of 

 ToRREYA a brief account of the appearance and life history of this 

 serious fungus disease of our native chestnut and characterized 

 the fungus under the name Diaporthe parasitica. Since that 

 time the disease has been reported from many additional localities, 

 and numerous inquiries have been made regarding its nature and 

 treatment. 



The origin of the disease and the center of its distribution are 

 still entirely unknown, while the area of its distribution is known 

 very imperfectly as yet and can be determined accurately only by 

 careful field explorations conducted by competent persons. The 

 amount of damage done by it, in and about New York city, 

 where it has been most carefully observed, probably reaches a 

 total of between five and ten million dollars. Of the numerous 

 splendid chestnut trees that once existed in the parks, woodlands, 

 and country estates of this region, it would be difficult to find 

 to-day a hundred perfectly healthy trees ; dead trees have been 

 cut by the hundreds during the last two years and the rest will 

 undoubtedly meet the same fate. 



Field studies indicate that the chestnut canker is spreading 

 rapidly. The summer spores are so minute and are produced so 

 continuously and abundantly throughout the growing season that 

 rapid distribution by the wind and other agencies is to be 

 expected. 



Not only the native chestnut, but also the European and 

 Japanese species, frequently planted in this country, and the 

 chinquapin, growing naturally from New Jersey southward, are 

 known to be subject to its attack. If the disease continues as it 

 has begun, there is, theoretically, no reason apparent why it 

 should not sweep from the country practically every tree, both 

 native and cultivated, of the genus Castanca. Let us hope, 

 however, that, in the economy of nature, something will intervene 

 to prevent this. 



