of serious water core, delay in cooling, holding at too high temperature, and 
holding beyond the normal storage life. 
Gerhardt and Allmendinger (57) tested the effect of a-naphthalene-acetic 
acid spray, as used for prevention of fruit drop, on ripening and storage physi- 
ology of Delicious apples, They concluded that if fruits are harvested within 
1 or 2 weeks after application of the spray, their storage physiology and degree 
of ripeness are not influenced by the hormone. However, if apples are left on 
the trees beyond a reasonable time, the spray will increase the rate of ripen- 
ing and the extent of losses from internal breakdown following water core. 
Bunemann and others (34) found that internal breakdown during storage 
was associated with low potash content and large fruits. 
Mattus (102), in Virginia, found that late harvesting and delayed stor- 
age were the principal factors causing internal breakdown of apples. 
Phillips (127) reported that the prevalence of breakdown (internal or 
mealy breakdown) in McIntosh apples during the 1956-57 storage season was 
associated with apples from orchards with light crops. 
Bramlage and Thompson (26) found that multiple boron sprays increased 
the incidence of internal breakdown of Jonathan apples during storage. 
Phillips and Poapst (128) stated that internal breakdown in Lobo apples 
increased as the temperature was increased between 30° and 39° F, More internal 
breakdown was found in earlier harvested fruits than in later harvested fruits. 
This is the opposite of what others have found. 
In studying the internal disorders of apples a clear distinction has 
been made in the United States between internal breakdown, internal browning, 
brown core, and soggy breakdown. 
Soggy breakdown may develop in certain varieties of apples such as 
Grimes Golden, Golden Delicious, and Northwestern Greening if they are stored 
at 32° F., or slightly lower. Much of the review that follows probably belongs 
with the section on soggy breakdown, but because of the uncertainty it is placed 
with internal breakdown. 
; In a paper presented at the International Institute of Refrigeration, 
van Schreven (171) discussed breakdown of apples and pointed out the need for 
clarifying the terminology. She studied only the Jonathan variety and found 
what appeared to be more than one type of breakdown. She attributed breakdown 
to low temperature and also to slight water core, but she did not discuss them 
separately. She also stated that a high catabolic activity seemed to indicate 
a high susceptibility to breakdown. 
In another paper van Schreven (172) reported two kinds of Jonathan 
breakdown: "glassy skin" and ''sponginess."' In general, the breakdown she 
described increased with a reduction in storage temperature, but delay in 
storing did not reduce the percentage of fruits affected. No relation was 
found between leaf and fruit content of nitrogen, phosphorous, potassium, cal- 
cium, and magnesium and the occurrence of breakdown. 
Tinsdale (165) states that low temperature during the first 2 months of 
storage caused severe flesh breakdown in Jonathan apples. 
Internal Browning 
Internal browning has been observed wherever Yellow Newtown apples are 
grown. It is of economic importance, however, only in the Pajaro Valley in 
California, where the weather is cool and cloudy during the growing season, 
and at times in Washington and Oregon. 
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