130 
Journal of Agricultural Research 
Vol. XXIX, No. 3 
delayed storage with free air movement 
over the apples served as a partial 
preventive for storage scald. Apples 
scalded less in boxes, baskets, hampers, 
and ventilated barrels than in the 
usual tight barrels. Increasing or de¬ 
creasing the oxygen content of the 
storage air had little or no effect upon 
scald; increasing the carbon dioxide 
content tended to decrease scald. 
Excessive humidity favored the devel¬ 
opment of scald but was not usually 
an important determining factor in 
its development. Injuries apparently 
identical with scald could be produced 
by exposing apples to the vapors of 
esters and other substances that were 
constituents of the odorous products 
of the apple. Scald was reduced by 
coating the apples with a thin film of oil 
but the appearance of the fruit was 
often injured by the treatment. Oiled 
blotter material scattered through the 
package reduced the scald without 
injury to the fruit. Packing the 
apples in oiled wrappers (carrying 15 
per cent or more of their weight in oil) 
was found to be the most satisfactory 
and efficient method of controlling 
scald. Ordinary unoiled wrappers were 
of little or no value in scald-control and 
paraffin wrappers far less efficient 
than the oiled ones. The value of the 
various oil treatments in scald-control 
was thought to depend largely upon 
the ability of the oils to absorb the 
odorous substances thrown off by the 
apples. The conditions leading up to 
scald were found to be of a cumulative 
nature, subject to remedial measures 
during the first six or eight weeks of 
storage but after that time often 
beyond remedy. 
Power and Chesnut (17) (1920) found 
that the odorous constituents of apples 
consisted essentially of the amyl esters 
of formic, acetic, and caproic acids, 
with a very small amount of the ca- 
prylic ester and a considerable propor¬ 
tion of acetaldehyde. In a later publi¬ 
cation (18) (1922) geraniol was added 
to the list of odorous constituents. 
Whitehouse (20) (1919) stored Iowa 
apples under different humidities and 
found that slightly more scald devel¬ 
oped with a relative humidity of 80 to 
90 than with a relative humidity of 60 
to 70. The degree of temperature had 
a much greater influence in the devel¬ 
opment of scald than the degree of 
humidity, a constant temperature of 
32° F. giving the best results. Wrap¬ 
ping apples delayed the appearance of 
scald and paraffin paper retarded the 
disease slightly more than the ordinary 
wrapper. 
A later report (11) (1922) from Iowa 
Agricultural Experiment Station stated 
that the use of oiled wrappers prac¬ 
tically controlled scald in all cases 
tested. 
Magness and Burroughs (18) (1922) 
pointed out the relation of wilting to 
scald resistance. They obtained more 
scald with apples exposed to a high 
humidity than with those exposed to 
a lower humidity, and were of the opin¬ 
ion that the effect of ventilation or air 
circulation in reducing scald might be 
main.v an action of drying of the sur¬ 
face of the fruit. 
Marble (14) (15) (1922), (1923) also 
emphasized the relation of wilting to 
scald resistance. He thought that low 
temperatures had a depressing effect on 
apples and lessened the resistance of 
certain varieties to scald. Ventilation 
was effective in preventing scald if the 
temperature was high enough for the 
variety. 
Adam (1) (1923) reported that Aus¬ 
tralian apples scalded more when im¬ 
mature than when mature. He found 
in agreement with others that scald was 
worse the higher the temperature, and 
that efficient ventilation practically 
eliminated the disease. 
Baker (2) (3) (1924) reported results 
confirming the efficiency of the oiled 
wrappers in scald control. In an 
experiment on Grimes apples he found 
that shredded paper gave practically 
as good scald control as the wrappers. 
EXPERIMENTAL RESULTS 
The commercial results of the past 
two years seem to indicate that the 
oiled wrapper has largely solved the 
scald problem so far as box apples are 
concerned but it does not meet the re¬ 
quirements of the barrel packer. Ex¬ 
periments extending over a period of 
six years have proved that the oiled 
wrappers will largely control scald as it 
occurs in the barrel package and some 
growers have found it profitable to pack 
their apples in this manner, but the diffi¬ 
culty of placing wrapped apples in 
barrels and the cost of the operation 
make the oiled wrapper impracticable 
so far as the general barrel trade is 
concerned. The situation has created 
an increased demand for a method of 
scald-control adapted to the barrel 
package. The first method that sug¬ 
gested itself for controlling scald apart., 
from the wrapper was that of applying 
the oil directly to the skin of the apples. 
A large number of tests of this sort 
were made and various mixtures of oils 
and waxes were tested. The results 
(10) were not satisfactory. In nearly 
