24 
BULLETIN 1253, U. S. DEPARTMENT OF AGRICULTURE. 
Table 24. — Summary of cars showing freezing injury, 1919 and 1920, by months. 
Month 
Box crop. 
Barrel crop. 
Total. 
1919 
1920 
1919 1920 
4 
425 
305 
259 
231 
24 
3 
11 
49 
56 
26 
13 
45 
31 
19 
17 
4 
3 
2 
60 
December .. 
22 
26 
20 
21 
1 
527 
January . __ ... . .. ... . 
406 
February. 
322 
March . .. . ... 
269 
April .... .. 
28 
May 
5 
Total i.. 
1,251 
155 
90 
121 
1,617 
i Total for 1919, 1,341 cars; total for 1920, 276 cars. 
SUMMARY. 
The foregoing analysis shows that so far as can be judged from 
inspections by the Bureau of Markets there is a great variety of 
diseases in the commercial apple crop of the United States and a 
rather heavy loss from disease in a portion of that crop. 
Considering the inspections for the four-year period as a whole 
blue-mold rot occurred more commonly than any other disease. In 
the box crop scald was second and decay third; in the barrel crop 
decay came second, followed by black-rot. 
Twelve diseases were reported in the box crop, 18 in the barrel 
crop, with 9 diseases common to both. 
The disease index in the barrel crop, 16.8, was a third larger than 
the corresponding number, 12.6, in the box crop. The difference be- 
tween the two seems to be due largely to the greater variety of rots 
in the barrel crop. 
Summer and fall varieties showed less disease, on the average, than 
winter or long-storage varieties. 
The box crop showed a steady increase in percentage of disease 
from October till June; the barrel crop only from December till June. 
Percentage of disease, particularly rots and scald in apples 
on the market seems to be largely a matter of length of storage 
period, those stored longest being most seriously affected. 
In the barrel crop the percentage of disease was less in cars from 
New York, Michigan, Virginia, and West Virginia than in those from 
all other Eastern States considered as a whole. 
The percentage of disease in the box crop was slightly heavier in 
cars from Idaho than in those from all other Western States con- 
sidered as a whole. 
Cars which went to southern inspection offices showed, on the 
average, more loss from disease than those which went to other in- 
spection offices. Differences between the two groups of offices were 
greater for the barrel than for the box crop. 
If percentage of scald is calculated on the basis of cars showing 
disease of any kind, it is found to be about the same in both crops. 
But if calculated on the basis of cars showing scald, it is more than 
twice as large in the barrel as in the box crop. 
Data from a relatively small number of cars indicate that large 
apples are more susceptible than small ones to blue-mold rot, decay, 
scald, internal breakdown, and water-core and that apples in the 
Fancy grade suffer more from scald than do those in the Extra Fancy 
grade. 
WASHINGTON : GOVERNMENT PRINTING OFFICE : 1924 
