JOURNAL OF AGMITIM, RESEARCH 
Vol. XXIX Washingtox, D. C., August 1, 1924 No. 3 
FREEZING INJURY OF APPLES 1 
By H. C. Diehl, Junior Physiologist, and R. C. Wright, Physiologist, Office of 
Horticultural Investigations, Bureau of Plant Industry, United States Depart¬ 
ment of Agriculture 
INTRODUCTION 
The growing and marketing of apples 
ire foremost among fruit industries of 
the United States, as shown by the 
tonnage of fruit raised, value of the 
crop, carlot shipments, and quantities 
exported. Most of the apples are 
moved in the autumn, with the peak 
of the movement in October and 
November, as shown by data for 1918 
to 1923 compiled by the Bureau of 
Agricultural Economics, United States 
Department of Agriculture. 2 However, 
considerable quantities are shipped in 
the colder months, and are thus liable to 
be exposed to low temperatures in tran¬ 
sit. Consequently, very considerable 
losses are suffered by the apple industry 
every year from freezing in transit. 3 
To this may be added the injury in cold 
and common storage houses when the 
temperature is allowed to fall below the 
freezing point of the fruit and to 
remain so for some time; also the 
injury from freezing when the fruit is 
still on the tree, which causes heavy 
losses in some districts. Detailed 
figures on the latter two sources of 
loss are as yet unavailable. 
In spite of the importance of the ap¬ 
ple industry, and the serious losses ren¬ 
dering protection for the fruit a matter 
of imperative necessity, the literature of 
the freezing problem as related to fruits 
has but few references to the apple. 
Miiller-Thurgau (7) 4 and Molisch ( 6 ) 
both made the observation that ripe 
apples may be exposed to a somewhat 
lower temperature without injury when 
thawed slowly than when the defrosting 
proceeds rapidly, but Chandler ( 1) was 
not able to demonstrate this for unripe 
apples. 
Greene (3) reported experiments to 
determine the effect of freezing upon 
the keeping qualities of apples in cold 
storage, and to fix the temperature be¬ 
low which injury to apples could be ex¬ 
pected to occur. He concluded that 
apples frozen on the tree could be stored 
safely provided the freezing was not too 
severe, that favorable weather followed 
it, and that thawing of the fruit had 
taken place gradually on the tree; also 
that apples frozen in cold storage at 24° 
F. or higher would show no injury if 
thawing took place graduallv from 29° 
to 31°. 
The investigations reported in the 
present article deal with determinations 
of the freezing points of most of our im¬ 
portant commercially grown varieties of 
apples, with a study of undercooling 
and its relation to injury, and a deter¬ 
mination of the effect of freezing on 
such matters as bruising of the fruit, 
visual injury, and keeping quality in 
storage, together with a discussion of 
the rate of cooling down and of freezing 
of apples in different types of packages 
under constant freezing conditions. 
1 Received for publication March 11,1924—issued January, 1925. 
2 Carlot shipments of apples in the United States for the months September to February of the years 
1918 to 1923, inclusive:* 
Year 
September 
October 
November 
December 
January 
February 
1918-19___ 
8,070 
26,680 
13,563 
6,320 
4,044 
3,679 
1919-20_ 
12, 259 
32, 666 
15, 854 
5,301 
4, 393 
4,419 
1920-21_ 
11,043 
37, 284 
23, 087 
8,875 
6,046 
6,698 
1921-22_ 
13,146 
35,117 
14, 464 
5,991 
4,189 
4,683 
1922-23.__ 
14, 787 
32, 052 
19, 512 
8, 229 
8, 438 
6, 257 
° Data compiled by the Bureau of Agricultural Economics, U. S. Department of Agriculture. 
3 Rose, D. H. diseases of apples on the market. U. S. Dept. Agr. Bui. 1253. 
* Reference is made by number (italic) to “ Literature cited,” p. 127. 
Journal of Agricultural Research Vol. XXIX, No. 3 
Washington, D. C. August 1, 1924 
Key No. G-383 
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