10 BULLETIN 587, U. S. DEPARTMENT OF AGRICULTURE. 
FACTORS AFFECTING THE DEVELOPMENT OF PHYSIOLOGICAL DECAY IN STORAGE. 
Physiological or old-age decay is shown in Plates IIT and YII. 
All fruit, if not otherwise destroyed, eventually decays physiologi- 
cally when it has passed through certain natural changes. It is es- 
sential to successful storage that these changes or ripening processes 
be retarded, as this is the fundamental principle upon which the cold 
storage of all fruits is based. 
(1) Soundness of fruit—One of the most important considera- 
tions in the control of physiological decay in storage is the selection 
of sound fruit of naturally long-keeping varieties. Such varieties 
as Rainier, Winesap, Arkansas Black, and Yellow Newton will, as 
is generally known, keep in good condition much longer than Grimes, 
Jonathan, and McIntosh. 
(2) Immediate storage compared with delayed storage—The 
promptness with which the fruit is stored and cooled after it is picked 
is the most important single factor in retarding physiological de- 
cay. After the apples are picked, a few days in the orchard or pack- 
ing houses may greatly shorten their cold-storage life, especially if 
the weather is hot and the fruit is left in a warm place. Plates VI 
and VII show the condition of Jonathan apples as regards ripeness 
and maturity when stored immediately after picking and when de- 
layed fer two weeks before storage. There was no difference in 
treatment or handling except for the delay of two weeks in the 
grower’s packing house before storing in the case of the apples 
shown in Plate VII. The life in cold storage of the immediately 
stored apples illustrated in Plate VI was at least a month longer 
than that of the delayed, Plate VII. There are few factors of greater 
importance than prompt cooling and storage in successfully prolong- 
ing the storage life of apples. 
(3) Storage at 32° and 35° F.—In principle and results the storage 
of apples at a temperature of 35° F. is comparable with delayed 
storage, 1. e., the slower the cooling and the higher the temperature 
at which the apples are held, the more rapidly will they ripen and 
death decay set in. Table IV gives the percentage of decay in com- 
parable lots of apples stored at the two temperatures. 
(4) Apples picked while immature compared with those picked at 
maturity.—Despite the fact that death decay is primarily the result 
of the completion of the life processes, it does not follow that apples 
picked previous to maturity will keep longer than fruit picked at 
maturity. Apples picked when immature, as previously noted, are 
usually very susceptible to scald. Severe scald is in turn very fre- 
quently followed by a peculiar type of physiological decay of the 
flesh directly beneath the scalded area. Plate II shows very clearly 
this type of physiological decay on a Rome Beauty. 
