344 
Journal of Agricultural Research 
Vol. I, No. 4 
prune agars, + 11, Puller's scale; Raulin’s fluid, malt, and string-bean 
agars; and cylinders of Irish potato, sweet potato, parsnip, and carrot, 
banana, orange, prune, and apple. 
Fig. 4 .—Diplodia longispora ; A section showing grouping of pycnidia. 
The Irish potato and the sweet potato gave the best results for the 
vegetables. The fruits gave an abundance of mycelial growth, but few 
pycnidia. In several media, espe¬ 
cially apple, peculiar sclerotial bodies 
(fig. 3) were formed in abundance. 
An extremely acid or extremely alka¬ 
line medium was not as satisfactory 
as a nearly neutral one, and starchy 
media in general gave the best re¬ 
sults. On all artificial media which 
produced pycnidia, a dense stroma 
was produced and the spores were 
borne in locules in the stroma. This 
is not the case on the host, where, 
while the pycnidia are usually 
grouped (fig. 4), a typical stroma is 
never present. On all media the 
colonies are at first hyaline, later 
becoming grayish green, and finally 
almost black. 
GERMINATION STUDIES 
The spores germinate readily in 
distilled water, corn-meal infusion, 
Raulin's fluid, and corn-meal, prune, 
or potato agar. If a diseased twig 
is placed in a damp chamber many 
spores will germinate inside the 
pycnidium. When placed in a liquid medium without being subjected 
previously to a moist atmosphere, the time varies from three to six hours. 
Fig. 5. —Diplodia longispora: Types of germination. 
A, B, Germ tubes from end of spore; C, germ 
tube from side of spore. 
