10 ‘‘ ROUGH-BARK ’’ DISEASE OF YELLOW NEWTOWN APPLE. 
used in the orchard experiment were covered with a paper sack for 
24 hours to prevent excessive drying out, while those used in the 
greenhouse were covered with a bell jar for the same length of time. 
The spots did riot seem to enlarge much, if any, but became gray 
with reddish margins. As shown in Plate I and in Plate III, figure 
1, such spots with numerous pycnidia are strongly suggestive of 
Phyllosticta, and indeed the fungus under such conditions might 
easily be mistaken for a Phyllosticta or a Phoma. When plates 
were poured and the fungus reisolated it fruited as a Phomopsis, 
having both Phoma spores and the long, slender, curved sort which 
Shear?! calls scolecospores. 
The fungus will also cause a rot of the apple. York Imperial 
apples, about one-third grown, very hard and green, were inoculated 
through needle pricks with spores from corn-meal cultures and then 
placed in moist chambers. In one month rotted spots from 0.5 to 1 
centimeter in diameter were noted about most of the points of 
inoculation, and on the larger spots the pycnidia of a fungus were 
quite conspicuous. (See Pl. III, fig. 3.) A microscopic examination 
of pycnidia and spores showed them to be identical with those of the 
fungus concerned in the inoculations. The pycnidia contained both 
the Phomalike and the long, slender, hooked spores, the latter being 
particularly abundant. Cultures from the margins of the rotted areas 
produced the fungus in pure culture, showing conclusively that it had 
been the cause of the decay. 
Full-grown but solid, not fully ripe, specimens of Yellow Newtown 
apples were inoculated by inserting spores through breaks in the skin 
and then placed in moist chambers. In two weeks rotted areas 
4 to 5 centimeters in diameter appeared about the points of inocu- 
lation, while the controls showed no decay. From the margins of 
these rotted spots also the fungus was reisolated in pure culture. 
Typical pycnidia and spores were also formed, as in the case of the 
green apples. It will thus be seen that the fungus, especially on ripe 
Yellow Newtowns, is able to produce considerable rotting, though 
such a rot apparently occurs seldom in nature. 
DESCRIPTION OF THE FUNGUS. 
On corn meal, corn-meal agar, and sterile apple wood the fungus 
rruits quite readily, but pycnidia formed naturally on apple branches 
are difficult to find, being rather obscure and apt to disappear rather 
quickly after spore discharge has taken place. 
The globose pycnidia develop singly or sometimes in a raised 
stroma, which may be from 0.5 to 1 centimeter across. They are 
1 Shear, C. L. The ascogenous form of the fungus causing dead-arm of the grape. Phytopathology, v. 
1, p. 116-119, 5 fig., 1911. 
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