APPLE DISEASES 
whole tree will have leaves streaked with 
yellow. 
Not pathological. 
Volutella Rot 
Volutellose 
A black rot of apples, closely imitating 
in appearance that caused by Sphaer- 
opsis, but differing from sphaeropsose in 
several details, is reported from South 
Carolina ! 
In general appearance the disease con- 
sists of a rotten black spot, the spot in- 
creasing in size until it eventually en- 
compasses the whole fruit. The central 
and older portions of the decayed region 
are of an intense coal black color. The 
younger region of the spot, its outer 
border, a zone about five-eighths of an 
inch wide, is brownish. 
Spray as for scab and black rot. 
THE WATER CORE OF APPLE 
P. J. O'GARA 
Water core of apple is a trouble which 
is not restricted to any one district where 
apples are grown, but is found to occur 
more or less generally over the country, 
particularly in the arid and semi-arid 
districts. Reports of this trouble have 
also come from apple-growing districts of 
Hurope, Asia and Africa. Although the 
trouble has been Known for some time, 
data of very little importance is to be 
found in American plant pathological and 
physiological literature. It seems that 
very little serious work has been done in 
the matter of determining the true cause 
of the disease. Some European writers 
have held that the disease is caused by 
bacteria, although others have shown that 
the trouble is not due to any parasitic 
agency. 
The writer has done considerable work 
on this disease during the past few years, 
and in no case has it been possible to 
identify any organism as the causative 
agent. Ail the methods known to modern 
bacteriology especially those used in the 
study of ultra-miscroscopic organisms, 
have failed to show the presence of any 
organism. Numerous attempts have been 
* North Carolina Experiment Station Bul- 
letin No. 206. 
493 
made to inoculate healthy fruits by in- 
jecting the juice from water-cored spots 
of diseased apples, but in no case did the 
inoculated fruits develop any symptoms 
of water core.(1) The writer has noted 
the presence of various organisms, espec- 
ially Alternarza sp., but in no case could 
it be shown that any organism caused 
the disease. 
The characteristic appearance of water- 
cored apples is so well known that a 
minute description is hardly necessary. 
The affected apples have hard watery 
areas extending outward from the outer 
edges of the seed cavities. In the begin- 
ning stages, the first appearance of water 
core is in connection with the vascular 
system. Each bundle will show a water- 
soaked area surrounding it, and, as a rule, 
this area makes its appearance a short 
distance from the stem. As the vascular 
system is variously branched upward, 
water-soaked areas may appear at almost 
any place in the fruit. In the later stages 
the seed cavity usually contains liquid, and 
the hard inner membrane of the carpels 
is cracked and covered with hair-like 
growths which finally assume a brownish 
appearance. The fruit has a somewhat 
sweetish, fermented flavor, and the watery 
parts contain more sugar and less acid 
than the normal or unaffected parts. It 
is during the later stages of the disease, 
especially where cracks appear in the ca- 
lyx or blossom end, that we find fungi and 
bacteria present. <Alternaria sp. is a com- 
mon intruder, and produces a serious core 
rot. This latter trouble, namely, Alterna- 
ria infection, may be prevented by the 
proper and timely application of Bordeaux 
mixture. 
It must be understood that no single 
condition may produce water core; as a 
rule, it is a@ combination of perhaps two 
or more factors. In some cases avoidance 
of the trouble may be possible; however, 
for the most part, it is entirely impossible 
to prevent it because of the fact that cer- 
tain climatological factors enter into the 
problem. The most prominent factors in- 
ducing water core are: 
(1) O’Gara, P. J. Water Core of Apple. 
Office of the Pathologist and Entomologist for 
Rogue River Valley, Medford, Oregon. Bulletin 
9. October 11, 1912 
