4 BULLETIN 57*7, U. S. DEPARTMENT OF AGRICULTURE. 
and that about 1 sack in 20 contained diseased tubers. A number 
of sacks were examined; most of them were free from disease; in 
only one sack was there more than one diseased tuber, and all the 
diseased tubers found had been wounded with the digging fork. 
The amount of leak in the car was considered too small to warrant 
sorting. 
The injured potatoes from the second and third cars were stored 
in the warehouse until September 18. They were then sorted and 
the uninfected potatoes sold. The data obtained from sorting the 
1,000 sacks of potatoes as they came from the field are summarized 
in Table I, which includes the data already given, together with that 
obtained in sorting the wounded tubers. 
Table I. — Experiments with 1,000 sacks of potatoes harvested in the usual way in Cal- 
ifornia, showing the results of sorting for the control of potato leak. 
Tubers injured — 
Rotten tubers (percentage based on estimate of 200 
Field- 
tubers to each sack) in three lots of those injured — 
In- 
Car of 
run 
pota- 
Shrink- 
jured 
tubers 
sorted 
tubers 
toes 
age in 
By 
remov- 
al of 
knobs. 
In 
field- 
run 
lots. 
By removal of knobs. 
By fork wounds. 
ket- 
(270 
re- 
quir- 
ed. 
sorting 
By 
fork 
wounds. 
sacks). 
Maxi- 
mum. 
Mini- 
mum. 
Average. 
Maxi- 
mum. 
Mini- 
mum. 
Average. 
when 
sorted. 
Per 
Num- 
Num- 
Num- 
Per 
Num- 
Num- 
Num- 
Per 
Sacks. 
Sacks. 
Sacks. 
Sacks. 
cent. 
ber. 
ber. 
ber. 
cent. 
ber. 
ber. 
ber. 
cent. 
Sacks. 
No. L... 
349 
11 
43 
25 
19.4+ 
23 
2 
12.5 
6.25 
61 
14 
40 
20 
56.5 
No. 2.... 
326 
5 
31 
20 
15.6+ 
40 
8 
17 
8.5 
75 
21 
48 
24 
40 
No. 3.... 
325 
4 
30 
21 
15.6+ 
35 
10 
19 
9.5 
68 
28 
49 
24.5 
40 
Table I shows that something more than 19.4 per cent of the pota- 
toes in the first lot sorted were wounded in harvesting, either by 
the removal of branches (knobs) or by the digging fork. The 
percentage of injured tubers in the other two lots, 15.6, is not quite 
so great. In all, 170 sacks of potatoes out of 1,000 were injured. 
That such a percentage of the potatoes should be injured in harvest- 
ing indicates exceedingly poor methods. Nor does this 170 sacks 
represent all the injured potatoes, as the tubers injured by fork 
wounds were supposed to have been sorted out in the field. Much 
of this damage might be eliminated with proper care, but as long as 
the potatoes are harvested with forks it is probable that there will 
be a high percentage of injured tubers. The digging of potatoes 
with machinery is practiced very fit tie in this region, though potato 
harvesters adapted to this type of soil and these conditions are said 
to be available. 
Of the 170 sacks of injured potatoes, 104 sacks (10.4 per cent of 
the total of 1 ,000 sacks) were injured by the removal of knobs. Break- 
ing off the knobs is a common practice in this region and is recom- 
mended by the potato buyers, as it results, of course, in a smoother 
potato. The tubers injured in this way are considered to be no more 
