Dec. 15,1923 
Control of Apple Scald 
521 
UNOILED WRAPPERS 
The tests with apples in the usual commercial wrappers as compared 
with unwrapped apples show r that these unoiled wrappers have practically 
no effect upon scald control. In the tests of Table I where the two condi¬ 
tions were compared the average degree of scald on the wrapped apples 
was 41 per cent and that on the unwrapped ones 42 per cent. 
UNOILED MEDICATED WRAPPERS 
The unoiled medicated wTappers were purchased in the northwestern 
market where they have been extensively sold on the ground that they 
have great preservative qualities. The average results of the comparable 
tests in the preceding table show 33 per cent of scald on the apples in 
unoiled wrappers and 23 per cent on the apples in unoiled medicated 
wrappers. 
PARAFFIN WRAPPERS 
Paraffin wnrapper No. 1 w-as made by soaking the usual commercial 
apple wrapper in hot paraffin; paraffin wrappers No. 2, 3, and 4 were 
supplied by paper companies; No. 2 was a heavy grade of paper and No* 
3 and 4 tissue grades similar to the paper used for wrapping lunches and 
apparently infiltrated with a low r melting point paraffin or a mixture 
of paraffin and oil. 
The paraffin wrappers have reduced the percentage of scald in all cases, 
but have shown only about half the efficiency of the mineral oil wrappers. 
An average for the comparable tests shows 42 per cent of scald on the 
apples in unoiled commercial wrappers, 20 per cent on the apples in the 
paraffin wrappers and no scald for those in mineral oil wrappers. 
MINERAL OIL WRAPPERS 
EFFECT UPON SCALD 
The scald control secured with the mineral oil wrappers is shown in 
detail in Table I and the relative efficiency of the various wrappers is 
brought out more clearly in Table II. In most cases these wrappers 
either entirely prevented the disease or reduced it to such an extent 
that it was no longer of importance from the market standpoint. In the 
total of 67 experiments there were four instances that probably should 
be noted as exceptions to this rule; two with eastern grown Stayman 
Winesap and two with eastern grown Arkansas (Mammoth Black Twig). 
In the 1921 and 1922 experiments with Stayman Winesap scald was 
reduced from more than 50 per cent on the unwrapped fruit to 4 to 16 
per cent on the fruit in the better grade of oil wrappers. In the 1919 
experiment with Arkansas scald was held in complete control by the oiled 
wrappers until January 10, when the unwrapped fruit showed 55 per 
cent of the disease, but by February 2 the apples in oiled wrappers had 
developed 18 to 25 per cent of scald as compared with 64 per cent on 
the unwrapped apples. In the 1922 experiment on Arkansas from 
Rockville, Md., the apples in oiled wrappers had developed about 20 
per cent of scald by February 17, while those that were unwrapped had 
75 per cent. These results with Stayman Winesap and Arkansas would 
appear to be fairly satisfactory when compared with the average data 
from disease-control measures, but they fall considerably short of the 
control secured in other oiled wrapper experiments, and in the case of 
the Arkansas the disease was not held sufficiently in check to prevent 
the apples from being offered at a discount in price. 
