CULTUEAL CHAEACTEES OF CHESTNUT-BLIGHT FUNGUS. 5 



PREVIOUS CULTURE WORK. 



Clinton, the Andersons, Pantanelli, and Fulton have already made 

 contributions to this subject. CHnton,^ 1908, describes cultures of 

 Endotliia parasitica on Lima-bean agar. Pycnospores were produced 

 and the growth gradually changed from whitish to a bright orange 

 color. The expelled pycnospores were described as lemon yellow, 

 later becoming a chestnut brown. In 1912 ^ and 1913 ^ Clinton de- 

 scribed cultures of E. gyrosa, which is the E. radicalis of the present 

 writers and will be so named hereafter in this paper, on potato, 

 Lima-bean, and oat agars. The following differences between this 

 species and E. parasitica were pointed out: E. parasitica fruited 

 earlier and more abundantly than E. radicalis and had more numer- 

 ous and smaller fruiting bodies than the latter; E. parasitica also 

 produced a less luxuriant aerial growth, the embedded mycelium 

 being much more highly colored. In his last paper, 1913,^ Clinton 

 gives further accounts of cultures, emphasizing the points already 

 mentioned and giving five differences in the behavior of the two. 

 The principal point, in addition to those just mentioned, is that E. 

 parasitica produces more abundant, earlier, smaller pycnidia, which 

 are embedded in the surface, while E. radicalis forms fewer, elevated, 

 distinct pustules, rarely hidden by the exuding spores. Cultures on 

 potato-juice agar, with various quantities of tannic acid, were also 

 compared. Clinton found that E. j)arasitica grew in higher percent- 

 ages of the tannic acid used and produced a more evident develop- 

 ment of mycelium than E. radicalis. 



The Andersons * pointed out the differences between cultures of 

 Endotliia parasitica and E. radicalis (E. virginiana) grown on potato 

 agar and on sterile chestnut twigs. They found practically the 

 same differences between the two organisms on the potato agar as 

 described by Clinton, though somewhat more detail is given in 

 regard to the development of the characteristic features. They 

 also pointed out, for the first tune, the differences in the growth of 

 the two species on sterile chestnut twigs. E. parasitica produced a 

 short, white, weblike growth on the surface of the twigs, with heav- 

 ier masses of mycelium, which later became orange colored where 

 pycnidia developed, while E. radicalis developed a fluffy orano-e 



1 Clinton, G. P. Chestnut-bark disease, D;aporthe parasitica Murr. Connecticut Agricultural Experi- 

 ment Station, 31st-32d Annual Reports, |190fi]-190S, p. .S79-S90, 1908. 



2 Clinton, G. P. The relationships of the chestnut-blight fungus. Science, n. s., v. 36, no. 939, p 

 907-914, 1912. 



3 Clinton, G. P. Chestnut-bark disease. Comiecticut Agricultural Experiment Station, Annual 

 Report, 1912, pt. 5, p. 422, 1913. 



< Anderson, P. J., and Anderson, H. W. The chestnut-blight fungus and a related saprophyte. Phj-- 

 topathology, v. 2, no. 5, p. 204-210, 1912. 



[Clr. i:Jl] 



