DISEASES OF APPLES ON THE MARKET. 
Table 3. — Disease in barrel and box crops, by years. 
Year. 
Cars. 
Rots. 
Scald. 
Other 
diseases. 
Disease 
index.' 
Box crop: 
1917. 
233 
219 
2,084 
1,138 
Per cent. 
8.7 
11.2 
7.3 
4.7 
Per cent. 
8.0 
1.9 
3.5 
7.7 
Per cent. 
0.7 
.2 
.1 
1.9 
17 5 
1918 
13.4 
1919. 
11.0 
1920 
14.4 
3,674 
6.8 
5.0 
.7 
12.6 
Barrel crop:. 
1917 
53 
117 
570 
808 
15.5 
11.3 
14.5 
7.3 
9.6 
1.1 
3.4 
5.0 
9.0 
3.3 
.5 
2.3 
34. 1 
1918 
15.7 
1919 
18.4 
1920 
14.6 
1,548 
10.5 
4.3 
1.9 
16.8 
i The disease index is not a true percentage but merely a sum of percentages (see p. 4) and is of value 
only as a basis of comparison between years, months, varieties, or any other coordinate elements in the 
tabulations. 
As with the box crop, the percentage of "other diseases" was low 
when calculated on the basis of all cars showing disease, but fairly 
high for some of them when calculated on the basis of cars showing 
that particular disease. For example (Table 2), there was an average 
of 16.8 per cent of Rhizopus rot in 24 cars, 19.3 per cent of blotch in 
17 cars, and 25.5 per cent of sooty blotch in 20 cars. 
The disease index in the barrel crop, 16.8, was a third larger than 
the corresponding number, 12.6, in the box crop. (Table 3.) 
o 
H 
> 
u 
Z) 
U 
o 
US 
< 
CO 
O 
z 
a 
< 5 
Fig. 1.— Box crop. Percentages of rots, scald, other diseases, and'disease index, by months, for the four 
crop years, 1917 to 1920, inclusive. The percentages are calculated on the basis of all cars showing disease 
of any kind. 
BOX CROP: DISEASE BY MONTHS. 
Rots. — With the two minor exceptions in December and March, 
there was a fairly regular increase (see Table 4 and fig. 1) from 3.8 
per cent in October to 8.5 per cent in June, a condition probably due 
to the further development in storage of rots already present when the 
fruit went into storage. It may have been due in part also to further 
infection during the storage period, but this seems unlikely, since 
most of the rotting was caused by blue mold, which, according to the 
