Jan. 12,1924 
IOI 
Effect of Cold Storage on Bean Weevils 
taken in November from a warehouse where the temperature was about 
65° F., while those showing mortalities of 40.43, 52.17, 68.86, 80.45, and 
85.13 per cent went into cold storage from a lower temperature in Feb¬ 
ruary. 
In Table I the perfect control obtained after 56 days at 32 0 F. is 
shown. Forty-six days’ exposure did not kill all the weevils within the 
beans, although, as previously stated, no live emerged adults were found. 
Table I .—Effect of a constant temperature of 32 0 F. on Bruchus obtectus 
Number of 
days in 
storage. 
Larvae. 
Pupae. 
Unemerged adults. 
Mortality, 
all forms. 
Num¬ 
ber 
alive. 
Num¬ 
ber 
dead. 
Mortality. 
Num¬ 
ber 
alive. 
Num¬ 
ber 
dead. 
1 
! 
Mortality. 
Num¬ 
ber 
alive. 
Num¬ 
ber 
dead. 
Mortality. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
7 
5 6 
154 
73-73 
25 
55 
68.75 
25 
33 
56.90 
69-54 
14 
15 
91 
85.85 
30 
52 
63.4I 
38 
65 
63.11 
71.48 
14 
14 
6 
30.00 
3 
6 
66.66 
II 
7 
38.89 
40-43 
22 
16 
29 
64.44 
II 
4 
26.66 
6 
3 
33-33 
5 2>I 7 
28 
I 
284 
99-65 
I 
152 
99-35 
12 
51 
80.95 
97.20 
31 
21 
32 
60.38 
6 
22 
78.57 
6 
19 
76.00 
68.86 
37 
14 
64 
82.05 
11 
34 
75 * 5 6 
1 
9 
90.00 
80.45 
46 
5 
36 
87.80 
3 
16 
84.21 
3 
11 
78.57 
85-13 
56 
0 
185 
100.00 
0 
82 
100.00 
0 
46 
100.00 
100.00 
56 
0 
265 
100.00 
0 
9 i 
100.00 
0 
29 
100.00 
100.00 
61 
0 
36 
100.00 
0 
26 
100.00 
0 
3 i 
100.00 
100.00 
Total 
T AO 
1,182 
90 
540 
1 
I 102 
*204 
X Utui • * * 
1 
results with storage at 36° E. 
Seven samples of beans were refrigerated at 36° F. for periods ranging 
from 14 to 66 days. At the first examination of the samples, which 
contained 28,703 beans, 2,199 weevils were found emerged—2,092 were 
dead and 107 alive. Samples exposed for 14, 22, 31, 37, and 46 days 
contained a sufficient number of live adults to reinfest the seeds. No 
live adults occurred among beans stored for 61 and 66 days. 
Subsequent examination of these samples showed that new emergence 
had taken place from beans stored for 14, 22, 31, and 37 days, and that 
none had occurred in the 46 and 61 day samples; but one live adult was 
found to have emerged from beans stored 66 days at 36° F. As shown 
in Table II, 200 beans from this sample contained no live larvae, pupae, 
or adults, and the presence of one live adult in the sack 3 months after 
removal from cold storage is regarded as accidental. 
The live weevils removed from samples at the time of the first examina¬ 
tion were kept under favorable conditions to test their powers of repro¬ 
duction. A few eggs were laid by females refrigerated for 32 days or 
longer, but all of these failed to develop. This fact tends to minimize 
the importance of the presence of a few feeble survivors. 
Table II gives the results of dissecting 200 beans from each sample 
stored at 36° F., and shows (as with 32 0 F.) that the length of exposure 
which killed all emerged adults was not sufficient to give perfect control 
of forms within the beans. As previously stated, 61 days’ refrigeration 
killed all emerged weevils, although some survived within the beans. The 
