CHESTNUT BARK DISEASE. 377 



chestnuts of European descent, and among these some resist 

 the blight pretty well; and some of the American progeny, 

 like the Hannum and Ridgely, seem to resist well enough, so 

 that I am grafting these upon many different sprouts." 



As interest became aroused, inquiries have been frequently 

 made if other trees than the chestnut, especially oaks, were 

 not attacked by this fungus. For a long time its occurrence 

 was not reported on any other host than Castanea. Even as 

 late as April, 1912, Metcalf (35, p. 223) published the following: 

 "So far as is now known, the bark disease is limited to the 

 members of the genus Castanea. The American chestnut, the 

 chinquapin, and the cultivated varieties of the European chest- 

 nut, are all readily subject to the disease. Only the Japanese 

 and some other East Asian varieties appear to have any 

 resistance." 



Fulton seems to have been the first to report the chestnut 

 blight on oak, having exhibited cultures in December, 1911, at 

 the Washington meeting of the American Phytopathological 

 Society. In his Harrisburg paper (24, p. 53) he reports finding 

 a fungus on white and black oak in Pennsylvania, and says 

 concerning it: "While it is desirable to carry on further cross 

 inoculation experiments, it seems reasonable to suppose in the 

 light of present evidence that Diaporthe parasitica may, under 

 unusual circumstances, establish itself saprophytically on por- 

 tions of trees outside the genus Castanea, if these portions are 

 already dead. We have found no evidence that the fungus 

 produces in any sense a disease of such trees as the oak." 



The writer and Mr. Filley first found the chestnut blight on 

 oak in October, 1912, at Middlebury, Conn., in a badly diseased 

 chestnut grove on the Whittemore estate. Previous search for 

 several years had failed to show it on any of the various species 

 of oak examined. At this place the fungus occurred rather 

 inconspicuously, as follows : ( I ) On an exposed living root 

 of Quercus alba that had been injured in some way; (2) On 

 cut surface of wood of a live stump of Q. rubra from which 

 young sprouts were growing; (3) On the dead bark and dead 

 stub of a twig on a recently cut stump of Q. rubra. Also, in 

 November of the same year, Mr. Walden, of the entomological 

 department, brought to the writer specimens of white oak from 

 Greenwich, Conn., that had been killed by drought, on which 

 this fungus occurred. 



